Base Force: now made with 37.5™ Technology, which is scientifically proven to give you more stamina. Made from 4-ounce, polyester. FastDry® with 37.5™ Technology makes this our fastest drying gear. Rugged Flex® technology for ease of movement. Fights odors. Fit is more supportive and closer to the body with smooth flatlock seams & tagless label to enhance comfort. Fly opening and gusset at inseam for comfort and easy movement.