Here's what other sites are saying:
A warm, stretchy polyester balaclava that's slim-fitting enough to fit under a winter climbing or ski helmet.. . . . 88% polyester, 12% spandex stretches to fit your head. Equivalent in warmth to lightweight fleece. Keeps your skin dry when you sweat. Highly breathable. Wind and abrasion resistant. Comfortable next to skin. Machine washable.