<prompt> Translate the following text to EnglishAchilless heel ni kwamba, bila nylon coating, haina upepo upinzani - upepo mdogo kwamba sufu na pamba ingekuwa kugeuka nyuma kukata haki kwa njia ya fleece na kuumwa mbaya.  <response>: Fleeces Achilles heel is that, without a nylon coating, it lacks any wind resistance--a slight breeze that wool and cotton would turn back cuts right through fleece with a nasty bite. 