"Polypropylene is the hottest thing in thermal underwear on the market! This government issue 100% polypropylene is 1/16 in. thick with a fleece texture next to your skin. Our troops use this material with their extreme cold weather gear. Polypropylene is designed to wisk away moisture from your skin to keep you warm and dry. Unused/Unissued. This cold weather Balaclava is made from the same 100% polypropylene as shirt and pants. Fits snug over your head with oval eye opening. Balaclavas are 16 in. long, enough to cover from the top of your head to your shoulders. Colors: Tan, Black. One size fits all."