Check the listing for details. US Military Polypropylene Cold Weather Undershirt Polypro Shirt Small 2002 295-A. Listed at 19.95 USD. Undershirt, Cold Weather 100% Polypropylene. This is a genuine U.S. Military, polypropylene, cold - wet weather shirt. Polypropylene is also color fast, so it will resist fading and continues to look good, even in chlorinated climates.