Down

Down is the fine under-plumage of ducks and geese — nature’s insulation, with a warmth-to-weight ratio synthetics still chase. The fill itself contains no plastic and biodegrades.

The catch is the package: down is usually wrapped in a synthetic shell fabric, typically nylon or polyester. A down jacket’s plastic score comes almost entirely from its shell and lining, so the composition line matters more than the word “down”.

Down fill scores 0/100. The product score weights all listed components — shell, lining, and fill — so a down parka with a nylon shell shows the nylon honestly.

The same weight applies everywhere: a product's score is the percentage-weighted plastic share of its listed fiber composition, and every weight is public.