# Balls

The 'Balls' label bundles unrelated equipment: basketball, soccer, volleyball, and football share inflatable-bladder construction and are chosen by official size number; baseball and softball differ by core and circumference; tennis, table tennis, golf, and bowling each run their own sizing and material rules. The sport decides every spec, never price or brand.

## How it works

Inflatable team balls (basketball, soccer, volleyball, football) work the same way: a rubber bladder is inflated through a valve, wrapped in reinforcing thread, and covered in leather, composite, or rubber panels sized and pressurized to the sport's rules. Baseball and softball have no bladder: a wound cork-rubber, kapok, or polyurethane core is covered in two stitched leather panels, and the seam's height and the ball's circumference are what change between levels and sports. Tennis balls are a felt-covered rubber shell, either pressurized with gas or solid and pressureless. A table tennis ball is a hollow 40mm poly sphere with no core at all. A golf ball is a layered solid — one core or several — under a dimpled cover, with no inflation and no bladder. A bowling ball is a weighted core cast inside a coverstock shell, then drilled to fit one bowler's hand.

## How an expert narrows the choice

```mermaid
timeline
  section 1 · Sport ball family
    team_inflated : ask Which team sport : skip Core material, Seam height, Size class, Pressurization, Material and grade, Construction (piece count), Compression feel, Coverstock, Weight class
    bat_and_ball : ask Baseball or softball : skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Pressurization, Material and grade, Construction (piece count), Compression feel, Coverstock, Weight class
    racquet_sport : ask Tennis or table tennis : skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Core material, Seam height, Size class, Construction (piece count), Compression feel, Coverstock, Weight class
    golf : ask Construction (piece count), Compression feel : skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Core material, Seam height, Size class, Pressurization, Material and grade, Coverstock, Weight class
    bowling : ask Coverstock, Weight class : skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Core material, Seam height, Size class, Pressurization, Material and grade, Construction (piece count), Compression feel
  section 2 · Which team sport
    basketball : ask Official size, Cover material, Channel/seam pattern : skip Official size, Panel construction, Ball class, Ball size level, Cover and lacing
    soccer : ask Official size, Panel construction : skip Official size, Cover material, Channel/seam pattern, Ball class, Ball size level, Cover and lacing
    volleyball : ask Ball class : skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball size level, Cover and lacing
    football_american : ask Ball size level, Cover and lacing : skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class
  section 3 · Baseball or softball
    baseball : ask Core material, Seam height, Size class
    softball : ask Core material, Seam height, Size class
  section 4 · Tennis or table tennis
    tennis : ask Pressurization : skip Material and grade
    table_tennis : ask Material and grade : skip Pressurization
```

1. **Sport ball family.** Team sport, bat-and-ball, racquet sport, golf, or bowling?
   The five families are built on entirely different mechanics — inflation, a wound core, felt over rubber, a dimpled solid, or a drilled coverstock — so this fork decides every other question.
   If team_inflated: ask Which team sport; skip Core material, Seam height, Size class, Pressurization, Material and grade, Construction (piece count), Compression feel, Coverstock, Weight class.
   If bat_and_ball: ask Baseball or softball; skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Pressurization, Material and grade, Construction (piece count), Compression feel, Coverstock, Weight class.
   If racquet_sport: ask Tennis or table tennis; skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Core material, Seam height, Size class, Construction (piece count), Compression feel, Coverstock, Weight class.
   If golf: ask Construction (piece count), Compression feel; skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Core material, Seam height, Size class, Pressurization, Material and grade, Coverstock, Weight class.
   If bowling: ask Coverstock, Weight class; skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class, Ball size level, Cover and lacing, Core material, Seam height, Size class, Pressurization, Material and grade, Construction (piece count), Compression feel.
   Skip if already known: a query that already names a specific sport ball, an earlier answer naming a sport.

2. **Which team sport.** Basketball, soccer, volleyball, or football?
   Basketball, soccer, volleyball, and football share inflatable-ball construction but diverge on size numbering, cover material, and panel or lacing details that only make sense once the sport is known.
   If basketball: ask Official size, Cover material, Channel/seam pattern; skip Official size, Panel construction, Ball class, Ball size level, Cover and lacing.
   If soccer: ask Official size, Panel construction; skip Official size, Cover material, Channel/seam pattern, Ball class, Ball size level, Cover and lacing.
   If volleyball: ask Ball class; skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball size level, Cover and lacing.
   If football_american: ask Ball size level, Cover and lacing; skip Official size, Cover material, Channel/seam pattern, Official size, Panel construction, Ball class.
   Skip if already known: an earlier answer naming one of the four team sports.

3. **Baseball or softball.** Baseball or softball?
   Baseball and softball share the same core and seam facets, but their size classes and typical core material differ enough that the sport is worth confirming up front.
   If baseball: ask Core material, Seam height, Size class.
   If softball: ask Core material, Seam height, Size class.
   Skip if already known: an earlier answer naming baseball or softball, a query naming a bat size, which implies the sport.

4. **Tennis or table tennis.** Tennis or table tennis?
   A tennis ball's pressurization and a table tennis ball's material and star grade are unrelated axes that only apply to one sport each.
   If tennis: ask Pressurization; skip Material and grade.
   If table_tennis: ask Material and grade; skip Pressurization.
   Skip if already known: an earlier answer naming tennis or table tennis/ping-pong.

## What to surface

### Sport ball family

Which broad family of ball this is: an inflatable team-sport ball, a bat-and-ball ball, a racquet-sport ball, a golf ball, or a bowling ball. Each family is built and judged on completely different terms — inflation pressure versus wound core versus dimpled shell versus coverstock — so this fork decides every spec that follows. [2] [19]

Values: team_inflated, bat_and_ball, racquet_sport, golf, bowling.
Question to ask: Team sport, bat-and-ball, racquet sport, golf, or bowling?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Derive from the product title and category breadcrumb (basketball, soccer ball, baseball, golf ball, bowling ball, etc.).
Title keyword match against the sport name covers nearly every listing; multi-sport sets list each ball separately.

### Which team sport

Which of the four common inflatable team-sport balls this is: basketball, soccer (association football), volleyball, or American football. Basketball is judged on grip and bounce, soccer on roundness and panel seams, volleyball on touch and flight, football on shape and lacing — the sport decides which of those axes to check next. [1] [3]

Values: basketball, soccer, volleyball, football_american.
Question to ask: Basketball, soccer, volleyball, or football?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Title keyword match ('basketball', 'soccer ball', 'volleyball', 'football').
Nearly always explicit in the title or category breadcrumb.

### Baseball or softball

Whether this is a baseball or a softball. A baseball is noticeably smaller than any softball and uses a different core; gloves and bats are sized to one or the other, so this fork decides the size-class facet that follows. [9] [11]

Values: baseball, softball.
Question to ask: Baseball or softball?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Title keyword match ('baseball' vs 'softball').
Always stated in the title.

### Tennis or table tennis

Whether this is a tennis ball or a table tennis (ping-pong) ball. Tennis balls are felt-covered and sized for an outdoor racquet swing; table tennis balls are a hard 40mm plastic sphere for a tabletop paddle game — nothing about one transfers to judging the other. [12] [14]

Values: tennis, table_tennis.
Question to ask: Tennis or table tennis?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Title keyword match ('tennis ball' vs 'table tennis'/'ping pong').
Always stated in the title.

### Official size

The regulation size number — 7, 6, 5, 4, or 3 — that sets a basketball's circumference and weight for a given age and league. Size 7 (29.5 in circumference, about 20–22 oz) is the men's high school, college, and pro standard; size 6 (28.5 in, about 18–20 oz) is the women's standard; sizes 5, 4, and 3 step down for younger kids, and the wrong size throws off dribbling and shooting mechanics for the player's hand. [1] [2]

Values: size_7_mens_official, size_6_womens_official, size_5_youth, size_4_grade_school, size_3_mini.
Question to ask: What size — 7, 6, 5, 4, or 3?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually stated directly as 'Size 7' or 'Official Size' in the title.
Title keyword/number match; default unlabeled adult balls to size 7.
Chart: position on a circumference scale, size 7 largest.

### Construction (piece count)

How many layered components the ball is built from: two-piece, three-piece, or four-plus-piece. Two-piece balls are the most durable and cheapest, built for distance and a slower short game; three-piece and four-plus-piece balls add layers that trade some durability and cost for more short-game spin and a softer feel that better players pay for. [15]

Values: two_piece, three_piece, four_plus_piece.
Question to ask: Two-piece, three-piece, or more layers?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Nearly always stated in the product title or description ('2-piece', '3-piece', '4-piece').
Title keyword/number match; default unlabeled balls to two-piece, the budget standard.
Chart: spin-vs-durability axis, two-piece most durable.

### Coverstock

The outer shell material, from least to most hook: plastic (polyester), urethane, reactive resin, or particle. Plastic is the straight-rolling spare/house-ball standard with the least hook and most control; urethane adds a gentler arc; reactive resin is the common performance-ball hook; particle adds grit for the strongest hook on heavily oiled lanes. [17] [19]

Values: plastic_polyester, urethane, reactive_resin, particle.
Question to ask: Plastic, urethane, reactive resin, or particle?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Nearly always stated in the product title or description.
Title keyword match; default unlabeled low-price balls to plastic/polyester.
Chart: hook-potential axis, plastic least, particle most.

### Weight class

The ball's weight band in pounds, from light (6–10 lb) to heavy (15–16 lb, the USBC regulation maximum). A ball that's too heavy for the bowler's hand strength loses accuracy and control; too light sacrifices pin-carrying power. Most adults bowl 14–16 lb; kids and beginners start at 6–10 lb. [17] [19]

Values: light_6_to_10lb, mid_11_to_14lb, heavy_15_to_16lb.
Question to ask: What weight — light, mid, or heavy?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Weight in pounds is almost always stated directly in the title.
Parse the stated pound number into a band; default unstated adult balls to the 14–16 lb heavy band.
Chart: weight scale in pounds, 16 lb USBC max.

### Cover material

What the outer panels are made of: full-grain leather, a synthetic composite, or rubber. Leather is the indoor standard but must be broken in and is ruined quickly outdoors; rubber is built for asphalt and cold weather at the cost of indoor feel; composite splits the difference for indoor/outdoor use. [1] [2]

Values: leather_indoor, composite_indoor_outdoor, rubber_outdoor.
Question to ask: Leather for indoor, or rubber for the park?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title keyword match ('leather', 'composite', 'rubber', 'indoor/outdoor').
Title keyword match; default to composite indoor/outdoor when unstated, the most common all-purpose cover.
Chart: durability-vs-feel axis, leather softest, rubber toughest.

### Official size

The size number — 5, 4, or 3 — that sets a soccer ball's circumference for an age group. Size 5 (68–70 cm circumference, 410–450 g) is the adult and IFAB/FIFA standard; sizes 4 and 3 are scaled down for youth play so the ball matches a smaller foot and leg swing. [3] [4]

Values: size_5_adult, size_4_youth, size_3_youth_mini.
Question to ask: Size 5 adult, or a youth size?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title keyword/number match ('Size 5', 'Youth').
Title match; default unlabeled adult balls to size 5.
Chart: circumference scale.

### Ball class

Which volleyball class this is: standard indoor, youth indoor, or beach. Standard indoor balls run 65–67 cm and 4.3–4.6 psi for a crisp, controlled touch; beach balls are slightly larger, softer (2.5–3.2 psi), and textured for grip in sand and wind; youth balls are a touch smaller and lighter for younger hands. [5] [6]

Values: standard_indoor, youth_indoor, beach.
Question to ask: Standard indoor, youth indoor, or beach?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title keyword match ('indoor', 'youth', 'beach').
Title match; default unlabeled balls to standard indoor.
Chart: firmness axis, beach softest.

### Ball size level

Whether this is an official-size football (pro, college, or high school) or a smaller youth/junior ball. Official balls run about 11 to 11.25 inches on the long axis, weigh 14 to 15 ounces, and are inflated to 12.5–13.5 psi; youth and junior balls are scaled down with no single fixed spec so a smaller hand can grip and spiral it. [7] [8]

Values: official_pro_college_hs, youth_junior.
Question to ask: Full-size, or a youth/junior ball?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title keyword match ('youth', 'junior', 'TDJ', 'Pee Wee' vs 'official size').
Title match; default unlabeled adult-marketed balls to official size.
Chart: size scale, official largest.

### Size class

The ball's circumference class: 9-inch baseball, 11-inch youth fastpitch softball, or 12-inch adult softball (fastpitch or slow-pitch). A baseball (9–9.25 in) is noticeably smaller than any softball; adult fastpitch and slow-pitch softballs are both 12 in, while youth fastpitch drops to 11 in — gloves and bats are sized to match, so the wrong class doesn't fit the game. [9] [11]

Values: baseball_9in, youth_fastpitch_softball_11in, adult_softball_12in.
Question to ask: A baseball, or an 11- or 12-inch softball?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title keyword/number match ('baseball', '11-inch', '12-inch', 'fastpitch', 'slow-pitch').
Title match on sport name and any stated inch size; default softballs with no size stated to 12-inch adult.
Chart: circumference scale, baseball smallest.

### Panel construction

How the cover panels are joined: traditional 32-panel stitching, thermally bonded (seamless) panels, or hand-stitched leather. Thermally bonded covers resist water absorption and keep a truer flight in wet conditions; traditional 32-panel stitched balls are cheaper and still the training standard; hand-stitched leather is the classic match-ball feel. [3]

Values: stitched_32_panel, thermally_bonded_seamless, hand_stitched_leather.
Question to ask: Stitched panels, or a seamless bonded cover?

Used as: filter, shown on the card. Data: needs research, backfill cost low. Look for it as: Rarely a stated field; 'thermally bonded' or 'hybrid' in the title signals seamless construction, otherwise assume stitched.
Keyword match on 'thermally bonded', 'hybrid', 'seamless'; default to stitched 32-panel when absent.
Chart: water-resistance axis, bonded highest.

### Cover and lacing

What the panels are made of and whether they're laced: leather with real laces, or composite/rubber, often with molded-on laces. Leather needs breaking in but grips best once it does; composite and rubber footballs skip the break-in, shed water, and survive all-weather youth and practice use at some cost to tackiness. [7]

Values: leather_laced, composite_rubber_molded.
Question to ask: Leather, or composite/rubber?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title keyword match ('leather', 'composite', 'rubber', 'synthetic').
Title keyword match; default to composite when unstated for youth-marketed balls.

### Compression feel

How hard or soft the ball's core is, graded low, mid, or high compression. Low-compression balls suit slower swings (under about 85 mph) for more distance and a softer feel; high-compression balls suit faster swingers (over about 105 mph) for more control; using the wrong compression for your swing speed can quietly cost distance. [15] [16]

Values: low_compression, mid_compression, high_compression.
Question to ask: Soft, medium, or firm-feeling ball?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Sometimes stated as a compression number (e.g., '70 compression'); otherwise implied by marketing ('soft feel', 'tour performance').
Keyword match on 'soft'/'low compression' vs 'tour'/'firm'; default mid-range balls to mid-compression when ambiguous.
Chart: swing-speed-match axis.

### Pressurization

Whether the ball is pressurized with gas inside a hollow rubber core, or pressureless with a solid rubber core. Pressurized balls bounce liveliest fresh from the can but lose bounce within weeks once opened; pressureless balls stay consistent for a full season, which is why ball machines and high-volume practice use them despite a slightly duller feel. [12] [13]

Values: pressurized, pressureless.
Question to ask: Fresh-can pressurized, or a durable pressureless ball?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Title/description keyword match ('pressureless', 'practice ball'); default to pressurized, since nearly all retail cans are.
Keyword match on 'pressureless'; everything else defaults to pressurized.
Chart: bounce-life-over-time axis, pressureless longest.

### Material and grade

The ball's material (poly plastic or older celluloid) and its star rating from one to three, three being competition grade. Since 2014 the ITTF has required non-flammable poly balls for sanctioned play; three-star balls are the tightest, most consistent, and bounce-tested for competition, while one- and two-star balls are cheaper training/recreational grades. [14]

Values: poly_three_star_competition, poly_one_two_star_training, celluloid_legacy.
Question to ask: Competition 3-star, or a training-grade ball?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Star icons and 'ITTF approved' usually appear on the packaging/title.
Count stars in the title/image; default unlabeled balls to one/two-star training grade.
Chart: consistency axis, 3-star highest.

### Channel/seam pattern

The depth and width of the molded grooves (channels) between a basketball's cover panels, separate from the cover material itself. Deeper, wider channels give fingers more traction for grip and spin control; shallower, narrower channels feel smoother to release — brands name this as its own spec, like Wilson's 'NBA Pro Seams', independent of leather versus composite. [18]

Values: deep_wide_channel, moderate_channel, shallow_narrow_channel.
Question to ask: Deeper grip channels, or a smoother seam?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Rarely a listing field; named as its own spec row ('Channel Construction') on brand spec sheets, not typical marketplace listings.
Not on most listings; default unlabeled balls to moderate channel when unstated.
Chart: grip-texture axis, deep/wide channel most textured.

### Core material

What the ball's center is made of: a cushioned cork-and-rubber core, kapok fiber, or polyurethane. Cork-and-rubber is the standard baseball core for a consistent, MLB-level bounce; kapok is the traditional softball core; polyurethane cores are a modern softball alternative that behaves more consistently in cold weather. [9] [11] [10]

Values: cork_rubber_core, kapok_core, polyurethane_core.
Question to ask: Cork-and-rubber, kapok, or polyurethane core?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Rarely stated; 'official league ball' usually implies cork-and-rubber or polyurethane, cheap practice balls may use kapok or unspecified fiber.
Not on most listings; infer from brand/grade (e.g., 'official league' vs 'practice/recreational').

### Seam height

Whether the stitched seam sits raised above the cover or lies nearly flat. A raised seam gives a pitcher's fingers grip to make a ball curve or sink; a flatter seam cuts air resistance for a truer, faster flight — mainly a batting-practice and machine-feed choice. [9]

Values: raised_seam, flat_seam.
Question to ask: Raised seam, or flat seam?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Rarely stated; 'raised seam'/'flat seam' sometimes appears for practice and pitching-machine balls.
Default regulation game balls to raised seam; flat seam is mainly a labeled practice/machine-ball feature.

## What you give up

- Reactive resin and particle coverstocks grip the lane for a strong hook that carries the pocket on heavy oil, but that same grip makes the ball harder to control on dry or house-condition lanes, where a plastic ball rolls straighter. [17] [19] Board branch: "More hook, less control on dry lanes".
- A two-piece ball is the most durable and travels farthest off the tee for a given swing, but a layered three- or four-piece ball spins more around the green and feels softer at impact — the trade most players pay extra for. [15] Board branch: "More spin and feel, less distance and durability".

## Words you will meet

- **Bladder**. The airtight inner bag that holds a ball's air; nearly all inflatable sport balls have one.
- **Butyl rubber**. A synthetic rubber used for ball bladders because it holds air far longer than natural rubber.
- **Channel construction**. The molded grooves between a ball's cover panels; deeper or wider channels add finger grip.
- **Thermally bonded**. Cover panels fused together with heat instead of stitched, giving a seamless, water-resistant surface.
- **32-panel construction**. The traditional soccer-ball design of hexagon and pentagon panels stitched together so the ball looks round from any angle.
- **Coverstock**. The outer shell of a bowling ball, which controls how much it hooks on the lane.
- **Reactive resin**. A bowling coverstock material that grips the lane surface for a stronger hook than plastic or urethane.
- **Radius of gyration (RG)**. A measure of how a bowling ball's weight is spread around its core, which affects how early it starts to hook.
- **Compression rating**. A golf ball's firmness grade, set by how hard its core layers are.
- **Pressurized ball**. A tennis ball with gas sealed inside its hollow core, giving a livelier bounce that fades once the can is opened.
- **Pressureless ball**. A tennis ball with a solid rubber core instead of sealed gas, so its bounce stays consistent for much longer.
- **Kapok**. A lightweight plant fiber once standard inside softball cores, now mostly replaced by cork-rubber or polyurethane.
- **Cushioned cork center**. A cork core wrapped in layers of rubber, the standard baseball core for a consistent bounce.
- **Raised seam**. Stitching that sits slightly above a baseball's or softball's cover, giving a pitcher's fingers grip to make the ball curve.
- **Fastpitch**. The windmill-pitch form of softball, played with an 11- or 12-inch ball depending on age group.
- **ITTF**. The International Table Tennis Federation, which sets the rules and ball standards for competitive table tennis.
- **celluloid**. An early flammable plastic once used for table tennis balls, replaced by poly plastic for sanctioned play after 2014.
- **USBC**. The United States Bowling Congress, the governing body that sets bowling ball weight and diameter limits.

## Where we made a call

- Most soccer balls above entry price use thermally bonded, seamless panels rather than traditional 32-panel stitching. (confidence low). Single-sourced to the Wikipedia Football (ball) article; a second brand or regulator source confirming the stitched-vs-bonded market split was unreachable this run. [3]
- Golf ball compression maps to swing speed in three bands: low under 85 mph, mid 85–104 mph, high over 105 mph. (confidence medium). Single-sourced to the Wikipedia Golf ball article's swing-speed guidance; USGA/R&A and brand fitting pages were unreachable this run (403/404). [15]
- Table tennis balls are rated one to three stars, with three-star poly balls reserved for ITTF-sanctioned competition play. (confidence medium). Single-sourced to the Wikipedia Table tennis article; the ITTF handbook itself, which would independently confirm it, was unreachable this run. [14]
- Adult fastpitch softballs run 12 in circumference; youth fastpitch balls run 11 in, lighter than either 12 in ball. (confidence medium). Single-sourced to the Wikipedia Softball article; a USA Softball or WBSC rulebook source confirming the exact figures was unreachable this run. [11]
- Basketball 'channel construction' (seam/groove depth and width) is a distinct spec from cover material and affects grip. (confidence medium). Single-sourced to one Wilson product spec sheet; a second brand's sheet confirming the same named spec row was blocked (403/JS shell) this run. [18]

## References

1. [Basketball (ball)](https://en.wikipedia.org/wiki/Basketball_(ball)) (primer). Supports: Size 7 circumference 29.5–30.3 in and weight 20–22 oz is the men's/pro/college standard; Basketballs have a butyl rubber bladder wrapped in nylon thread under a leather or composite cover; Balls are made for indoor (leather/composite) or outdoor (rubber) use.
2. [Basketball](https://en.wikipedia.org/wiki/Basketball) (primer). Supports: Official men's ball is 29.5 in circumference and 22 oz; women's is 28.5 in and 20 oz.
3. [Football (ball)](https://en.wikipedia.org/wiki/Football_(ball)) (primer). Supports: Size 5 adult ball is 68–70 cm circumference, 410–450 g, inflated 8.7–16.1 psi; Most modern soccer balls are stitched from 32 panels.
4. [Laws of the Game: The Ball](https://www.theifab.com/laws/latest/the-ball/) (regulator). Supports: Confirms the ball spec: 68–70 cm circumference, 410–450 g weight, 0.6–1.1 atm pressure at sea level.
5. [Volleyball (ball)](https://en.wikipedia.org/wiki/Volleyball_(ball)) (primer). Supports: Standard indoor ball is 65–67 cm, 260–280 g, 4.3–4.6 psi; beach ball is softer at 2.5–3.2 psi.
6. [Volleyball](https://en.wikipedia.org/wiki/Volleyball) (primer). Supports: Confirms indoor volleyball circumference 65–67 cm and internal pressure 4.26–4.61 psi.
7. [American football (ball)](https://en.wikipedia.org/wiki/American_football_(ball)) (primer). Supports: NFL ball is inflated 12.5–13.5 psi and weighs 14–15 oz; four leather panels laced over a bladder.
8. [American football](https://en.wikipedia.org/wiki/American_football) (primer). Supports: Confirms the ball is inflated 12.5–13.5 psi and weighs 14–15 oz; college/high school balls run slightly smaller.
9. [Baseball (ball)](https://en.wikipedia.org/wiki/Baseball_(ball)) (primer). Supports: Regulation baseball is 9–9.25 in circumference, 5–5.25 oz, cork/rubber core, cowhide cover, 108 stitches; Seam height affects how much a pitcher can make a ball curve or sink.
10. [Baseball](https://en.wikipedia.org/wiki/Baseball) (primer). Supports: Confirms baseball is about 9 in circumference with a rubber/cork center wound in yarn under cowhide.
11. [Softball](https://en.wikipedia.org/wiki/Softball) (primer). Supports: Adult fastpitch softball is 12 in circumference, 6.25–7.0 oz; youth fastpitch is 11 in, lighter; Softball core may be kapok, cork-and-rubber, or polyurethane.
12. [Tennis ball](https://en.wikipedia.org/wiki/Tennis_ball) (primer). Supports: ITF diameter 2.57–2.70 in, weight 1.98–2.10 oz; felt-covered rubber, pressurized or pressureless.
13. [Tennis](https://en.wikipedia.org/wiki/Tennis) (primer). Supports: Confirms ITF ball diameter 2.575–2.700 in and weight 56.0–59.4 g.
14. [Table tennis](https://en.wikipedia.org/wiki/Table_tennis) (primer). Supports: Ball is 40 mm, 2.7 g poly plastic since 2014, rated one to three stars for competition.
15. [Golf ball](https://en.wikipedia.org/wiki/Golf_ball) (primer). Supports: Conforming ball must weigh ≤45.93 g and have diameter ≥42.67 mm per USGA/R&A rules; Balls are built two-, three-, or four-piece; compression maps to swing speed.
16. [Golf](https://en.wikipedia.org/wiki/Golf) (primer). Supports: Confirms USGA/R&A govern equipment and use the term 'conforming' for approved balls.
17. [Bowling ball](https://en.wikipedia.org/wiki/Bowling_ball) (primer). Supports: USBC caps weight at 16 lb and diameter at 8.500–8.595 in; Coverstock hook order, least to most: plastic, urethane, reactive resin, particle.
18. [NBA Official Game Basketball — product spec sheet](https://www.wilson.com/en-us/products/nba-official-game-basketball-wz10025) (spec sheet). Supports: Lists 'Channel Construction: NBA Pro Seams' as its own spec row, distinct from cover material.
19. [Ten-pin bowling](https://en.wikipedia.org/wiki/Ten-pin_bowling) (primer). Supports: Confirms USBC ball diameter 8.500–8.595 in and weight maximum of 16 lb.