Check the listing for details. US Military Polypropylene Cold Wet Weather Undershirt Polypro Large 2003 295-J. Listed at 24.95 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.