I'm looking right at the tag inside the bra "Main & pocketing fabric : 69% Polymide. 31% Spandex. Exclusive of elastic and/or decoration". To put a further point on it - Polymide is a man made fabric similar to nylon and does not breathe in hot weather, neither does Spandex. Besides all of that it's not a "light weight" bra by any stretch of the imagination. The stays sewn into the sides, under the arms, are stiff and miserable. This is undoubtedly the ugliest bra I've ever seen, I'm 72 and started wearing bras in the late 1950s - believe me, I know an ugly bra when I see it. Amoeba, or whoever is responsible for the product description on the Amazon site should be ashamed of themselves!