Our single-layer polypropylene thermal long underwear is uniquely engineered to keep you warm and dry during outdoor activities such as hunting, fishing, skiing and running. Because the extraordinary wicking ability of this polypropylene fabric draws moisture away from your skin, you stay warmer and dryer than with cotton thermals. It's also perfect for layering under other clothes for extra warmth. This thermal bottom is in navy blue. Please see our matching tops and alternate colours as well. Please note waistband may be grey, white or blue.