These foilage green extended cold weather clothing system (ECWCS) polypropylene "long john" thermal long underwear pants keep our soldiers warm when they are on duty, so you know they'll be great for your outdoor tasks. This is heavy duty stuff made for the coldest temperatures. The fleece is comfortable while the polypropylene material contains plenty of tiny air pockets to keep an insulating layer of heat around your skin. We also stock black and brown. These thermals have elastic waist bottoms and come in a range of sizes. Matching shirts are also available.