Scope: "Condoms" = barrier contraceptive/STI-protection sheaths, split into external (worn on a penis) and internal (worn inside the vagina or anus) products; excludes lubricants, dental dams as a standalone product, and spermicide sold separately (sibling leaves).

Seed: 1) The condoms equivalent of "weave not thread count" is material, not brand/flavor: latex vs. polyurethane vs. polyisoprene vs. nitrile decides allergy safety, oil-lubricant compatibility, and feel, while nominal width is the generic trap (buyers chase it like thread count, but length and shape ride along and ISO only requires ±2mm tolerance). 2) A field biologist who thinks in what survives abuse in the rain would notice shelf life and storage sensitivity first — that latex is a biologically-aged rubber product with a ticking 3-5 year clock accelerated by heat/UV, not a static commodity.

Sources:
[wiki_condom] https://en.wikipedia.org/wiki/Condom — materials (latex/polyurethane/polyisoprene/lambskin), oil-lubricant damage to latex, spermicide/N-9 HIV caution, FDA Vytex/flavored approvals, textured/studded, failure rates (18%/2% infobox) — fetched excerpt
[wiki_female_condom] https://en.wikipedia.org/wiki/Female_condom — internal condom structure (inner/outer ring, 17cm pouch), nitrile FC2, FDA 2018 reclassification to Class II "single-use internal condom", vaginal/anal use, failure rates (21%/5%) — fetched excerpt
[guttmacher] https://www.guttmacher.org/fact-sheet/contraceptive-effectiveness-united-states — male condom typical-use 13%/perfect-use 2%; internal condom typical-use 21%/perfect-use 5% — fetched excerpt
[path_iso4074] https://www.path.org/publications/files/RH_condom_wrkshp_session5_en.pdf — ISO 4074 Clause 5 (length >160mm, width nominal ±2mm, default width 53mm), Clause 6 (air inflation test, AQL 1.5%, extra-strong class) — fetched excerpt (PDF)
[onecondoms_sizechart] https://onecondoms.com/blogs/education/condom-size-chart — nominal width definition, brand size table (45-64mm width, 120-235mm length), "hyperthin" line — fetched excerpt
[scienceinsights_sizes] https://scienceinsights.org/what-sizes-are-condoms-snug-standard-and-xl/ — snug 40-49mm / standard 49-53mm / large 54-60mm nominal width categories, length 170-220mm typical — fetched excerpt
[condomsuk_shelflife] https://condoms.uk/blogs/sex-education/do-condoms-expire-shelf-life — shelf life by material: latex/polyurethane 5yr, polyisoprene 3yr, spermicidal 3yr, nitrile 5yr, lambskin 1yr; ISO 4074:2026 accelerated-aging test (180 days at 50°C) — fetched excerpt
[wiki_spermicide] https://en.wikipedia.org/wiki/Spermicide — WHO: spermicidally-lubricated condoms should no longer be promoted but are better than no condom — fetched excerpt
[plannedparenthood] https://www.plannedparenthood.org/learn/birth-control/condom — flavored condoms not for vaginal/anal use (yeast/BV risk), lambskin does not protect against STIs, dental dam can be made by cutting open a condom — fetched excerpt

Branches: condom_type -> external leg supported by wiki_condom (latex/polyurethane/polyisoprene/lambskin material section) and path_iso4074 (ISO 4074 applies to latex male condoms); internal leg supported by wiki_female_condom (nitrile FC2 structure, separate FDA device class).

Noise: color/novelty prints — cosmetic, no functional bearing, left off both brand pages' comparison tables. Pack quantity (3/10/12/24ct) — generic retail variant, not expert judgement, same pattern in unrelated categories. Shape/reservoir-tip terminology (straight-walled vs. contoured) — only single-sourced to one brand's base/middle/head taper spec (onecondoms_sizechart); dropped for insufficient corroboration. ASTM D3492/D6324 standard numbers — could not get a direct fetched confirmation (globalspec page blocked, 403); kept certification_standard facet to ISO 4074/FDA/WHO/CE only, which are directly confirmed. Internal condom reusability as a standalone facet — folded into a judgement instead since current regulatory labeling (single-use) supersedes older material claims and isn't a live buyer decision.

Corrections (2026-10-26):
- `material` split/facet cold_start_question changed from binary "latex or non-latex" to naming all five values ("Latex, polyurethane, polyisoprene, nitrile, or lambskin?") so the answer actually disambiguates the branch's `when` values.
- `material` branch `when` expanded from `["polyurethane","nitrile"]` to all five named materials, since `lubricant_compatibility` is a direct lookup from material for every value, not just those two.
- `nominal_width_fit.source` changed from `listing` to `researched`; its own `listing_field_hint` already said the band is rarely a stated listing field, so `listing` mislabeled it per the listing-vs-researched house rule.
- Added a `Polyurethane` vocabulary entry to match its sibling non-latex materials (Polyisoprene, Nitrile, Lambskin condom), which already had one.
- `condom_type` → `internal` branch now adds `length` to `makes_irrelevant`: the facet's >160mm rule is scoped to the external/ISO-4074 regime, and internal condoms weren't sized on this axis at all.
- `nominal_width_fit`'s `extra_large` value collapsed into `large`: scienceinsights_sizes, the only source for the bands, merges "Large and XL" into one 54-60mm band with no separate extra_large threshold, and no second source was found to support a distinct one — collapsing avoids inventing a range rather than leaving an unsourced value in place.