Scope: "Coolers, Insulated Bags & Lunch Boxes" (supplies > household > coolers) — hard-sided coolers/ice chests, soft-sided coolers/insulated bags (totes, backpack coolers), and personal lunch boxes/bags. Experts judge each on different specs, so one register, three facet sets routed by `container_type`.

Seed:
1. The coolers equivalent of harvest date: claimed ice-retention days — a marketing number rarely tested to a standard, where real-world performance runs about half the claim (switchback_best_coolers).
2. A nurse would notice first that a "BPA-free, phthalate-free, lead-free" liner claim on a kids' lunch box isn't decoration — CPSIA Section 108 actually regulates phthalates in child-care articles, so an unlabeled liner is a real unknown, not a cosmetic gap.

Sources:
[wikipedia_cooler] https://en.wikipedia.org/wiki/Cooler — rotomolded = one seamless piece; traditional = foam between plastic shells — fetched excerpt, line 659/678
[igbc_bear_resistant] https://www.igbconline.org/bear-resistant-products/ — certification tests effort a grizzly must expend; not a bear-proof guarantee — fetched excerpt, line 432
[wikipedia_lunchbox] https://en.wikipedia.org/wiki/Lunch_box — vacuum bottles paired with lunch boxes; evolved glass-lined steel to all-plastic by 1970s — fetched excerpt, line 720/739
[wikipedia_vacuumflask] https://en.wikipedia.org/wiki/Vacuum_flask — near-vacuum gap between double walls blocks conductive/convective heat transfer — fetched excerpt
[packit_freezable_classic] https://packit.com/products/freezable-classic-lunch-box — ECOFREEZE gel built into walls; PVC/BPA/phthalate/lead-free; collapses flat — fetched excerpt, line 10548/10578
[outdoorgearlab_best_cooler] https://www.outdoorgearlab.com/topics/camping-and-hiking/best-cooler — tests to FDA 40°F / 50°F-beer thresholds; measured 2.4–6.8 days to 40°F; no-gasket lets water leak — fetched excerpt, line 2534-2610/856
[switchback_best_coolers] https://www.switchbacktravel.com/best-coolers — rotomold=one piece vs injection=multi-piece; claimed retention 2–10 days, real-world ~half; 2:1 ice-to-food ratio; Tundra 65 is IGBC-certified with 2" walls — fetched excerpt, line 1180-1245
[cpsc_cpsia] https://www.cpsc.gov/Regulations-Laws--Standards/Statutes/The-Consumer-Product-Safety-Improvement-Act — Section 108 sets phthalate limits for toys and child-care articles — fetched excerpt, line 929

Branches:
- container_type → hard_cooler routes to shell/latch/drain/wheels/bear-cert facets (sentence: rotomolded vs injection-molded fused-piece vs multi-piece, switchback_best_coolers).
- container_type → soft_cooler routes to carry_style/liner (sentence: soft coolers trade ice days for weight/price/cost, switchback_best_coolers "Hard-Sided vs. Soft-Sided").
- container_type → lunch_box routes to cooling-mechanism/liner-safety facets, makes ice_retention_days irrelevant (sentence: lunch boxes judged on mechanism not multi-day retention, packit_freezable_classic).
- ice_retention_need → extended_week_plus pulls in bear_resistant_certification (sentence: multi-day/remote trips are where IGBC storage rules apply, igbc_bear_resistant).
- lunch_cooling_mechanism → vacuum_insulated_container makes food_contact_liner_material irrelevant (sentence: a vacuum bottle's double metal wall has no plastic liner to assess, wikipedia_vacuumflask).

Noise (spec-sheet/comparison rows left out):
- Price — excluded per rule, never a facet.
- Brand, overall star rating — excluded per rule (rating).
- "Other sizes" (SKU variant list) — catalog detail, not a buyer-judged attribute.
- Cup holders, bottle openers, cargo nets, dry-goods baskets, tie-down slots — accessory add-ons, not core to any one container type.
- Warranty length — a real comparison axis (switchback has a "Cooler Warranties" section) but the page truncated before that section loaded; not verified, left out.
- Interior height for standing a wine bottle upright — real but folded into capacity_qt's why_experts_care rather than its own facet.
- Floats on water — mentioned once for one soft-cooler model (RTIC Ultra-Tough), too niche/single-sourced for a facet.

Corrections (2026-10-26):
- lunch_cooling_mechanism: added a scope note to the facet definition and backfill_note so a standalone vacuum flask/thermos sold on its own routes to the `bottles` sibling leaf, not here; the lunch-kit vacuum bottle stays in scope.
- can_capacity: lowered range min from 12 (unsupported) to 22, confirmed against outdoorgearlab_best_cooler's "Measured Can Capacity" comparison table (fetched raw HTML; row values include 22 as its lowest entry).
- empty_weight_lb: lowered range max from 50 (unsupported) to 41, confirmed against switchback_best_coolers' spec rows ("Weight: 41 lb.", a 60qt rotomolded model); outdoorgearlab's measured-weight table tops out lower at 36.6 lb, consistent with 41 as the evidenced ceiling.
- capacity_servings: reclassified `source` from `listing` to `researched` since its own listing_field_hint already describes an inference from dimensions, not a present listing field.
- Added a vocabulary entry ("40°F / 50°F cold line") naming the FDA food-safety and cold-drink thresholds that outdoorgearlab_best_cooler tests ice_retention_days against; previously only buried in that reference's supports text.
- Added a `warranty_type` facet (lifetime / limited_multi_year / unspecified) wired into the hard_cooler and soft_cooler branches, sourced to switchback_best_coolers' "Cooler Warranties" section (Orca/Roam lifetime; most brands 1-10 years, Yeti 5 years), fetched and confirmed directly this run. Single-sourced; not independently corroborated by a second review site, disclosed in the facet's backfill_note.