Weatherproof Men's Therma Poly Stretch Mid Weight Base Layer Separates 92% polyester, 8% spandex Machine wash warm with like colors. Use non-chlorine bleach when needed. Do not use fabric softener. Tumble dry low. No iron. Weatherproof's Therma base layer transports moisture away from your body Keeps you warm, dry and comfortable Flat non chafing seams and tagless labels for comfort Stretchable insulating layer allowing freedom of movement Moisture management and odor control