Thinsulate 40 gram Beanie Winter Hats, One size fits all Black. Made of 100% Acrylic, Lining is 65% Polypropylene and 35% Polyster. These hats can be washed at 40 degrees C. We use these Hats on the nursery ideal for all outdoor activities where wearer generates / builds up a lot of body heat through activity or cold conditions. Will not absorb water so ideal for high activity or just out walking.