Stohlquist Men's Short Sleeve P2 Insulated Shirt P-2 Polyolefin (100% polypropylene) Like beefy lycra, but with bolder performance!P-2 transports moisture away from the body faster and more effectively than any other fiber!P2 has the highest insulating power -of any fiber, natural or man made. P2 fiber is strong, with excellent abrasion resistance -low bulk, and extremely durable. Iis inert, does not retain odor and does not support the growth of odor causing bacteria. Hand wash soap and water China