# Magnets & Magnetic Supplies Loose project magnets, flexible magnetic sheet or tape, and magnetic clasps are three different products sold under one label, each judged by a different spec. Material (neodymium versus ceramic/ferrite) sets how strong and how corrosion-prone a magnet is; form factor sets whether grade, adhesive backing, or locking even apply. ## How it works A rigid permanent magnet (neodymium or ceramic/ferrite) is magnetized once during manufacture and holds that field indefinitely; neodymium packs far more field per volume but corrodes without plating and weakens above roughly 80 to 220°C depending on grade, while ceramic ferrite is weaker but cheap and corrosion-resistant. A flexible magnetic sheet or tape is ferrite powder bound into a rubber or vinyl strip, then run past a drum of magnets that stamps narrow alternating north/south stripes into it, so it grips a matching strip of itself or a steel surface but is far weaker than a solid magnet of the same size. A magnetic clasp hides a small rigid magnet (usually nickel-plated neodymium) inside two halves of a jewelry or garment fastener; the halves snap together under magnetic pull alone, so nothing mechanically locks them shut unless the clasp adds a separate safety catch. ## How an expert narrows the choice ```mermaid timeline section 1 · Product form raw_magnet : ask Magnet material, Neodymium grade, Heat rating, Magnet shape, Coating / finish, Mounting feature, Pull force class : skip Sheet form, Adhesive backing, Printable surface, Holds best to, Clasp mechanism, Locking safety catch, Strand capacity, Closure scale flexible_sheet_or_tape : ask Sheet form, Adhesive backing, Printable surface, Holds best to : skip Neodymium grade, Heat rating, Magnet shape, Coating / finish, Mounting feature, Pull force class, Clasp mechanism, Locking safety catch, Strand capacity, Closure scale clasp_or_closure : ask Clasp mechanism, Locking safety catch, Strand capacity, Closure scale : skip Neodymium grade, Heat rating, Magnet shape, Coating / finish, Mounting feature, Pull force class, Sheet form, Adhesive backing, Printable surface, Holds best to section 2 · Magnet material neodymium : ask Neodymium grade, Heat rating ceramic_ferrite / alnico : skip Neodymium grade, Heat rating section 3 · Main job jewelry_or_sewing_closure : skip Pull force class mounting_or_hanging : ask Pull force class, Mounting feature ``` 1. **Product form.** Loose magnets, flexible sheet or tape, or a clasp? Loose magnets are judged by grade and coating, sheet/tape by adhesive and print surface, and clasps by mechanism and locking. Almost nothing else on the register applies to more than one of these. If raw_magnet: ask Magnet material, Neodymium grade, Heat rating, Magnet shape, Coating / finish, Mounting feature, Pull force class; skip Sheet form, Adhesive backing, Printable surface, Holds best to, Clasp mechanism, Locking safety catch, Strand capacity, Closure scale. If flexible_sheet_or_tape: ask Sheet form, Adhesive backing, Printable surface, Holds best to; skip Neodymium grade, Heat rating, Magnet shape, Coating / finish, Mounting feature, Pull force class, Clasp mechanism, Locking safety catch, Strand capacity, Closure scale. If clasp_or_closure: ask Clasp mechanism, Locking safety catch, Strand capacity, Closure scale; skip Neodymium grade, Heat rating, Magnet shape, Coating / finish, Mounting feature, Pull force class, Sheet form, Adhesive backing, Printable surface, Holds best to. Skip if already known: a query naming 'magnet', 'magnetic sheet/tape/roll', or 'clasp/closure', an earlier answer naming a grade, adhesive backing, or clasp type. 2. **Magnet material.** Neodymium (strongest), ceramic/ferrite, or alnico? Neodymium's grade and heat-suffix system only exists for neodymium; ceramic/ferrite and alnico have no equivalent and trade strength for corrosion resistance and cost instead. If neodymium: ask Neodymium grade, Heat rating. If ceramic_ferrite or alnico: skip Neodymium grade, Heat rating. Skip if already known: an earlier answer naming neodymium, NdFeB, ceramic, ferrite, or alnico, a query already naming an N-grade (e.g. N42, N52). 3. **Main job.** Craft decor, mounting something, a jewelry/sewing closure, or science/education? Use sets how much pull force actually matters: a fridge magnet needs almost none, a tool-mounting magnet needs a stated holding spec, and a closure needs a locking decision instead of a strength number. If jewelry_or_sewing_closure: skip Pull force class. If mounting_or_hanging: ask Pull force class, Mounting feature. Skip if already known: an earlier answer naming fridge magnets, favors, mounting, hanging, or jewelry/garment closures. ## What to surface ### Product form Whether the item is a loose rigid magnet, a flexible magnetic sheet/roll/tape, or a clasp-style closure with a magnet hidden inside it. Each form is compared on different specs entirely. Asking this first avoids asking about grade on a clasp or locking mechanism on a loose disc magnet. [1] [2] Values: raw_magnet, flexible_sheet_or_tape, clasp_or_closure. Question to ask: Loose magnets, flexible sheet or tape, or a clasp? Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Derive from the title: 'disc/block/ring magnet' vs 'magnetic sheet/roll/tape' vs 'magnetic clasp/closure'. Title keyword match covers nearly every listing; 'magnetic snap' or 'magnetic closure' in a sewing context maps to clasp_or_closure. ### Main job What the buyer mainly wants the magnet to do: decorate (fridge magnets, favors), mount or hang something, or close a piece of jewelry or garment. Decor needs almost no pull force; mounting needs a stated holding spec sized to the load; a closure needs a locking decision instead of a strength number at all. [1] Values: fridge_or_decor_craft, mounting_or_hanging, jewelry_or_sewing_closure, science_or_education. Question to ask: Craft decor, mounting something, a jewelry/sewing closure, or science/education? Used as: top-level split, filter. Data: needs research, backfill cost low. Look for it as: Usually implied by the marketed category ('fridge magnet kit', 'mounting magnets', 'magnetic jewelry clasps') rather than a stated field. Keyword-match the title and category name against the four values. ### Magnet material What the magnet itself is made of: neodymium (NdFeB rare-earth), ceramic/ferrite, alnico (aluminum-nickel-cobalt), or the bonded-ferrite rubber used in flexible sheet, or unspecified. Neodymium has roughly 3 to 4 times the remanent field of ceramic ferrite of the same size (1 to 1.5 T versus about 0.35 T) but corrodes without plating and loses strength above about 80 to 220°C depending on grade; ferrite is far weaker but cheap, corrosion-resistant, and tolerates heat to roughly 300°C; alnico is weaker again but tolerates over 540°C. [4] [5] Values: neodymium, ceramic_ferrite, alnico, bonded_flexible_ferrite, unspecified. Question to ask: Neodymium (strongest), ceramic/ferrite, or alnico? Used as: top-level split, filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title ('Neodymium Disc Magnets', 'Ceramic Ring Magnets'). Title keyword match; a bare N-grade number (N42, N52) in the title implies neodymium even without the word. Chart: position on a strength-vs-corrosion-resistance axis, neodymium strongest, ferrite most corrosion-resistant. ### Magnet shape The physical form of a loose magnet: disc, block/cube, ring, cylinder/rod, sphere/ball, bar, countersunk disc (with a tapered screw hole), or pot/cup magnet (set in a steel housing). Shape decides how the magnet is handled and mounted: a countersunk disc takes a flathead screw flush to the surface, a pot magnet concentrates the field on one face through a steel cup for far more pull than a bare disc of the same magnet, and a sphere is the shape most associated with the swallowing hazard because loose sets of them are marketed as building toys. [1] Values: disc, block_or_cube, ring, cylinder_or_rod, sphere_or_ball, bar, countersunk_disc, pot_or_cup_magnet. Question to ask: What shape: disc, block, ring, or something else? Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title ('1/2in Disc Magnet', 'Countersunk Ring Magnet'). Title keyword match against the eight values. ### Mounting feature How the magnet attaches to something else: bare with no feature, a countersunk screw hole, a plain through-hole, a factory adhesive pad, a threaded stud, or a pot/cup housing. A bare magnet needs glue or a holder; a countersunk hole takes a flush screw; a threaded stud or pot housing is built for repeated mechanical mounting (tool hooks, signage) rather than a one-time craft bond. [1] Values: none_bare, countersunk_screw_hole, through_hole, adhesive_backed_pad, threaded_stud, pot_or_cup_housing. Question to ask: Bare magnet, or does it have a hole, stud, or adhesive pad? Used as: filter. Data: on the listing, backfill cost low. Look for it as: Stated in the title for anything other than a bare magnet ('Threaded Stud Magnet', 'Self-Adhesive Magnet'). Title keyword match; default to none_bare when nothing is mentioned. ### Sheet form How flexible magnetic material is cut and sold: a flat sheet, a roll, a narrow strip/tape, or precut shapes (dots, squares). A sheet or roll is meant to be cut to a custom shape by the buyer (signage, printed photo magnets); tape is meant to be applied as a thin strip along an edge (card-making, closures); precut shapes skip cutting entirely for small, repetitive craft projects like favors. [6] Values: sheet, roll, strip_or_tape, precut_shapes. Question to ask: A flat sheet, a roll, narrow tape, or precut shapes? Used as: filter. Data: on the listing, backfill cost low. Look for it as: Stated in the title ('Magnetic Sheet 12x12', 'Magnetic Tape Roll', 'Magnetic Dots'). Title keyword match against the four values. ### Adhesive backing Whether the magnetic side opposite the magnetized face carries adhesive: none (bare magnetic material, for buyers who will glue it themselves), permanent pressure-sensitive adhesive, or a removable/repositionable adhesive. Permanent adhesive bonds instantly but cannot be repositioned once pressed down hard, which matters for anything that needs trimming or re-alignment first; bare material lets the buyer choose their own glue for porous or textured surfaces the adhesive won't grip. [6] Values: none_bare_magnet_side, permanent_adhesive, removable_adhesive. Question to ask: Does it come with sticky backing, or is it bare? Used as: filter. Data: on the listing, backfill cost low. Look for it as: Stated in the title ('Self-Adhesive Magnetic Sheet') or a bullet point; absence usually means bare. Keyword match 'adhesive', 'self-adhesive', 'sticky-back'; default to none_bare_magnet_side when absent. ### Heat rating The letter suffix after the grade number (none, M, H, SH, UH, EH, AH) that states the maximum temperature the magnet can run at before it starts to permanently weaken: about 80°C for standard grades, rising to 220°C for the AH suffix, K&J's highest. A standard-grade neodymium magnet demagnetizes faster than most buyers expect once it sits against a warm surface (a sunny car dashboard, a glue gun, a kiln shelf); a higher suffix costs more but keeps its pull at temperatures that would quietly weaken a standard grade. [1] [4] Values: standard_80C, M_100C, H_120C, SH_150C, UH_180C, EH_200C, AH_220C, unspecified. Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Appended to the grade in the title or specs ('N42SH'); absence of a letter means the standard 80°C rating. Regex the grade for a trailing letter combination; default to standard_80C when the grade is bare. Chart: position on a temperature-tolerance scale. ### Coating / finish What protects the magnet's surface: nickel-plated (nickel-copper-nickel, the default for neodymium), zinc-plated, epoxy-coated, plastic-coated, rubber-coated, gold-plated, or bare/uncoated (typical for ceramic or alnico). Bare sintered neodymium corrodes along its grain boundaries and can crumble to powder in moisture; plating or a polymer/lacquer coating is what makes most commercial neodymium magnets usable outdoors or near skin at all, and a rubber or plastic coat also cuts the pinch-injury risk a bare metal edge carries. [2] [4] Values: nickel_plated, zinc_plated, epoxy_coated, plastic_coated, rubber_coated, gold_plated, uncoated_ceramic_or_alnico. Question to ask: Plain metal, or coated in plastic/rubber/epoxy? Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually in the title ('Rubber Coated Disc Magnet'); absence of a coating word on a neodymium listing means standard nickel plating. Title keyword match; default neodymium to nickel_plated and ceramic/alnico to uncoated_ceramic_or_alnico when unstated. ### Printable surface The finish on the non-magnetic face of a flexible sheet: matte and printable (inkjet/laser), glossy laminate, a dry-erase/whiteboard coating, or plain magnetic material with no print finish. Only a matte-printable or laminated face is meant to carry a photo or logo through a home printer or copier; plain material is for buyers who will paint it, cover it, or leave it as-is, and a dry-erase face turns the same sheet into a reusable note surface instead of a one-time print. [6] Values: matte_printable, glossy_laminate, dry_erase_coated, plain_magnetic_only. Question to ask: Do you need to print on it, or is it plain? Used as: filter. Data: on the listing, backfill cost low. Look for it as: Stated in the title or bullets ('Printable Magnetic Sheet', 'Dry Erase Magnetic Roll'). Keyword match; default to plain_magnetic_only when no print/erase claim is made. ### Clasp mechanism How a magnetic clasp's two halves are shaped: a barrel/cylinder two-piece, a round or oval pair, a fold-over hook style, a double-ball pair, or another shape. A barrel clasp hides the join inside a tube so it reads as a continuous piece of jewelry; round, oval, fold-over and double-ball styles sit flatter against fabric, which matters more for a garment or bag closure than a necklace. [8] Values: barrel_two_piece, round_or_oval, fold_over, double_ball, other_shape. Question to ask: Barrel, round/oval, fold-over, or double-ball clasp? Used as: filter. Data: on the listing, backfill cost low. Look for it as: Usually in the title ('Magnetic Barrel Clasp', 'Double Ball Magnetic Clasp'); a jewelry-findings retailer's own SKU names confirm barrel, round/oval, fold-over and double-ball as real distinct shapes. Title keyword match against the five values; default to barrel_two_piece when unstated, the most common form in retail listings. ### Locking safety catch Whether the clasp relies on magnetic attraction alone to stay shut, or adds a separate mechanical safety catch on top of the magnet. A magnet-only clasp can be pulled open by a snagged sleeve or a hug, risking a lost bracelet or necklace; adding a safety catch (a small hook or figure-eight chain) keeps the piece attached even if the magnetic join pops open, which matters most for anything worn loosely or by someone with reduced grip strength who chose magnetic for ease of use in the first place. Values: magnetic_only_non_locking, magnetic_with_safety_catch. Question to ask: Just the magnet, or does it have a backup safety catch? Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Stated in the title or bullets ('with Safety Chain') when present; most budget clasps omit it and are magnetic_only_non_locking. Not confirmed against a fetched source this session; keyword match 'safety chain/catch/clasp' and default to magnetic_only_non_locking when absent. ### Strand capacity How many strands of beading wire or cord the clasp's loops are built to take: a single strand, two to three, or four or more. A single-strand clasp on a multi-strand piece forces the strands to bunch at one small loop, which looks crowded and stresses the wire; a clasp rated for the actual strand count spreads the load across separate loops sized for it. [8] Values: single_strand, two_to_three_strand, four_plus_strand. Question to ask: How many strands does it need to hold? Used as: filter. Data: on the listing, backfill cost low. Look for it as: Stated in the title or bullets ('3-Strand Magnetic Clasp'); a jewelry-findings retailer's own filter for these clasps is literally 'Number of Holes/Loops: 1-strand, 2-strand, 3-strand, 4-strand'. Keyword match for a strand count; default to single_strand when unstated. ### Closure scale The size class the clasp is built for: small jewelry hardware, a medium bag or garment closure, or a heavy-duty upholstery/leatherwork snap. Jewelry-scale clasps are sized and plated to match beading findings and are too weak and too small to serve as a bag flap or jacket closure; upholstery-scale magnetic snaps are sewn into fabric with mounting tabs and hold far more pull than any jewelry clasp needs. Values: jewelry_small, bag_or_garment_medium, upholstery_or_heavy_duty. Question to ask: Jewelry, a bag/garment, or heavy upholstery work? Used as: filter. Data: needs research, backfill cost medium. Look for it as: Implied by the marketed category ('jewelry clasp' vs 'purse snap' vs 'upholstery magnetic snap') more than a stated field. Not confirmed against a fetched source this session; keyword-match the title and category name against the three values. ### Safety hazard The dominant injury risk for this item: a small, very strong magnet (choking/internal-pinch risk if swallowed, especially in multiples), a large magnet (external pinch/crush risk between two magnets), pacemaker/ICD interference risk, or low risk at typical craft strength. Multiple small high-field magnets swallowed together can pinch bowel tissue between them and require emergency surgery, which drove a 2012 CPSC rule (later vacated in court) and a standing advisory against under-14 use; large magnets slamming together can break skin or bone; any neodymium magnet can interfere with a pacemaker or ICD at close range. [2] [7] Values: small_strong_choking_pinch_risk, large_pinch_crush_risk, pacemaker_icd_caution, low_risk_light_craft_strength. Used as: shown on the card, filter. Data: needs research, backfill cost medium. Look for it as: Rarely a stated field; infer from magnet_material plus shape/size (small spheres and discs in neodymium are highest risk) and from any choking-hazard warning text on the listing. Default small (under ~10mm) neodymium pieces to small_strong_choking_pinch_risk, large blocks/rings to large_pinch_crush_risk, flexible sheet and clasps to low_risk unless marketed as a loose magnet set. ### Neodymium grade The N-number (N35 through N52, plus heat-suffix variants) that states a neodymium magnet's maximum energy product, i.e. how strong it is for its size. Higher numbers mean more field per volume: N52 has roughly 49% more maximum energy product (BHmax, in MGOe) than N35 at the same size, so a buyer can shrink the magnet instead of the grade when space is tight. Grade is the single number most craft neodymium listings lead with. [1] [3] Values: N35, N38, N40, N42, N45, N48, N50, N52, unspecified. Used as: filter, shown on the card, sortable. Data: on the listing, backfill cost low. Look for it as: Stated directly in the title or specs for nearly every neodymium listing ('N42 Disc Magnet'). Title regex for N\d{2}; default to N35 (the weakest common grade) when the title says only 'neodymium' with no number, since budget listings skew weak. Chart: position on a strength scale, N52 strongest. ### Pull force class A rough holding-strength bucket for the specific magnet: light craft duty, medium duty, or heavy duty, as distinct from the material-level strength difference captured by magnet_material and grade. A buyer mounting a sign or a tool needs the stated pull force at a given size to exceed the load several times over; a buyer making fridge magnets or favors needs almost none. This is the number most loose-magnet listings state directly (in lb, oz, or kg) and is driven by material, grade, and size together, not material alone. [1] Values: light_craft_duty, medium_duty, heavy_duty. Used as: filter, shown on the card. Data: on the listing, backfill cost medium. Look for it as: Most loose-magnet listings state a pull force figure directly (e.g. 'holds 12 lb'); bucket it into the three classes by rough magnitude. Without a stated figure, default small discs/thin sheet to light_craft_duty and large blocks/rings in high grades to heavy_duty. Chart: position on a strength scale. ### Magnetization direction Which way the poles run through a loose magnet's body: axially (through its flat face, the default), diametrically (across a ring's or disc's diameter), or through its thickness (for blocks). A diametrically magnetized disc or ring has its poles on the curved side instead of the flat faces, so it grips, stacks and rotates completely differently from the far more common axially magnetized version of the same shape. [9] Values: axial, diametric, through_thickness. Used as: filter, shown on the card. Data: on the listing, backfill cost medium. Look for it as: Most listings are axial and say nothing; the title calls out 'diametric' or 'diametrically magnetized' when it isn't. Default to axial when unstated; keyword-match 'diametric' or 'through thickness' for the other two. ### Holds best to Whether a flexible magnetic sheet or tape grips a plain steel surface best, or grips a matching strip of itself best, as a result of how it was magnetized. Flexible magnet is stamped with narrow alternating north/south stripes rather than one uniform pole, so its field barely reaches past its own surface; it holds noticeably better against another piece of magnetized sheet (the common closure trick for bag flaps and fabric books) than it does against a steel sheet or fridge, where only the stray field at each stripe edge actually grips. [6] Values: holds_best_to_steel, holds_best_to_matching_magnet. Used as: shown on the card. Data: needs research, backfill cost medium. Look for it as: Not a stated field; default flexible sheet/tape/roll to holds_best_to_matching_magnet unless the listing specifically markets it as a fridge or whiteboard magnet, which implies a backing layer tuned for steel. Infer from the marketed use (fridge/whiteboard vs closure/book) rather than any stated spec. ## What you give up - Neodymium packs 3 to 4 times the field of ceramic ferrite into the same size, but it corrodes without plating, weakens above about 80 to 220°C depending on grade, and costs more; ferrite stays cheap, rust-proof, and heat-tolerant to around 300°C at a fraction of the pull. [4] [5] Board branch: "More corrosion-resistant, less strong". - A magnet-only clasp opens and closes with no fine motor control, which is exactly why it's marketed to people with arthritis or limited grip, but a snag or a hug can pull it apart with nothing holding the two halves together afterward; adding a safety catch keeps that convenience while catching a piece that pops open. [2] Board branch: "More secure, less one-handed convenience". ## Words you will meet - **Gauss**. A unit of magnetic field strength; retailers often state a magnet's 'surface field' in gauss to describe how strong it feels right at its face. - **Pull force**. The straight-line force needed to pull a magnet off a steel surface, usually stated in pounds; the number most buyers actually compare. - **Neodymium (NdFeB)**. A rare-earth alloy of neodymium, iron and boron; the strongest commercially available permanent-magnet material. - **Ferrite / ceramic magnet**. A cheap, corrosion-resistant magnet made from iron-oxide ceramic; much weaker than neodymium but immune to rust. - **Alnico**. A magnet alloy of aluminum, nickel and cobalt; weaker than neodymium but tolerates very high heat without losing strength. - **Grade (N-rating)**. The number after the N in a neodymium magnet's name (like N42); higher means a stronger magnet for the same size. - **Curie temperature**. The temperature at which a magnet loses its magnetism entirely; the maximum operating temperature sits well below it. - **Countersunk hole**. A tapered hole in a magnet sized so a screw head sits flush with the surface instead of sticking up. - **Pot / cup magnet**. A magnet set inside a steel cup that channels its field to one open face, giving far more pull per magnet than a bare disc. - **Pressure-sensitive adhesive (PSA)**. A sticky coating that bonds on contact with hand pressure alone, no water or heat needed; the usual backing on self-adhesive magnetic sheet. - **ICD**. An implantable cardioverter-defibrillator; like a pacemaker, its operation can be disrupted by a nearby strong magnet. - **Barrel clasp**. A clasp shaped like a short cylinder that splits into two halves and pulls together magnetically or by twisting. - **Remanent field (remanence)**. The magnetic field a material keeps on its own right after being magnetized, with no outside field left applied; the main number used to compare magnet strength by material. - **Maximum energy product (BHmax)**. A single number in MGOe summing up how much usable magnetic energy a material stores per unit volume; the basis for a neodymium grade's N-number. ## Where we made a call - Neodymium magnets hold roughly 3 to 4 times the field per volume of ceramic/ferrite magnets of the same size. (confidence high). Derived by comparing remanence figures (neo ~1.0-1.5T vs ferrite ~0.35T) rather than stated directly as a ratio by either source. [4] [5] - Small, strong loose magnets sold in sets pose a real swallowing/internal-pinch risk to children, which has repeatedly triggered (and lost) US regulatory action. (confidence medium). A 2012 CPSC rule was vacated in 2016; a 2020 petition response proposed a 2022 rule vote, but no later text shows one adopted, so status stays unsettled rather than a stable binding limit. [2] [7] ## References 1. [Neodymium Magnet Specifications](https://www.kjmagnetics.com/neodymium-magnet-specifications.asp) (spec sheet). Supports: Grade table N35-N52 (+M/H/SH/UH/EH/AH) with Br, Hci, Hci-intrinsic, BHmax; Thermal table: N=176F/80C, NM=212F/100C, NH=248F/120C max operating temp. 2. [Neodymium Magnet Safety](https://www.kjmagnetics.com/neodymium-magnet-safety.asp) (spec sheet). Supports: Pinch/crush injury risk, choking hazard for children swallowing multiple magnets, pacemaker/ICD interference; Brittle and can shatter; standard nickel-copper-nickel plating is not waterproof; nickel allergy risk. 3. [Magnet Grades](https://www.kjmagnetics.com/blog/magnet-grade) (primer). Supports: Grade letter prefix meaning: N=neodymium, C=ceramic, SmCo=samarium cobalt; grade number is BHmax in MGOe. 4. [Neodymium magnet](https://en.wikipedia.org/wiki/Neodymium_magnet) (primer). Supports: Strongest commercially available permanent magnet; remanence ~1.3T typical, up to 1.0-1.5T range; Grades N28-N55 with M/H/SH/UH/EH/TH temperature-suffix system up to 230C; Coatings: nickel, nickel-copper-nickel, zinc plating, polymer/lacquer coatings; Hazards: pinch/crush injury from larger magnets, chip/shatter risk, swallowing injury in children. 5. [Ferrite magnet](https://en.wikipedia.org/wiki/Ferrite_magnet) (primer). Supports: Hard/ceramic ferrite magnets: cheap, corrosion-resistant, brittle, max B field about 0.35 tesla; Widely used in household products such as refrigerator magnets. 6. [Magnet](https://en.wikipedia.org/wiki/Magnet) (primer). Supports: Flexible magnet: ferrite powder in a polymer binder, extruded as a sheet and magnetized with alternating N/S stripes; Maximum usable temperature order: alnico >540C, ferrite/SmCo ~300C, NdFeB ~140C, flexible ceramics lower. 7. [Buckyballs (toy)](https://en.wikipedia.org/wiki/Buckyballs_(toy)) (primer). Supports: CPSC regulatory history: 2012 rule restricting rare-earth magnet size in consumer products, vacated by federal court in 2016; CPSC advisory against under-14 use after ingestion incidents rose following the rule's vacatur; 2020 CPSC petition response proposed a 2022 rule vote; no later text shows one adopted. 8. [Magnetic Clasps (jewelry findings category page)](https://www.firemountaingems.com/jewelry-supplies/findings/clasps/magnetic-clasps/) (retail listing). Supports: Real filter 'Number of Holes/Loops': 1-strand, 2-strand, 3-strand, 4-strand clasps sold; SKU names show barrel, round, oval, double-ball, fold-over, rectangle, reef-knot clasp shapes. 9. [Magnetization Directions](https://www.kjmagnetics.com/magdir.asp) (primer). Supports: Disc/cylinder/ring magnets can be axially or diametrically magnetized; Block and arc magnets can instead be magnetized through their thickness.