MAXIT Thermal Shirt with Mock Neck and Long Sleeves 92% Polypropylene Far Superior to any other base layer, cold gear snow shirt MAXIT Thermal Shirt provides maximum warmth without bulky layering Comfortable, stretchable, cotton-like PROMAX IV fabric with flat seam construction Proven in the harsh conditions of the NFL and the Candadian Football League The best quick-dry, moisture transport shirt availablebar none!