Seger Sports Women's Acrylic Beanie with Polarec Grid Back and Windstopper Technology 70% Acrylic/30% Wool Imported Hand Wash Official sponsor of the Swedish national ski team One size fits all Wind stopper is a very thin, lightweight membrane that provides total wind protection and excellent ventilation simultaneously. The membrane's micro pore structure keeps cold wind out while allowing moisture to escape, keeping you dry, warm, and comfortable Polarized is a highly functional fleece material with extensive breathing capacity. It keeps the head dry and cool even when one performs at one's best, and it isolates and heats when it's cold. 4-way stretch give full mobility as well as perfect fit. So caps with polartec power stretch are ideal for all kinds of sport activates