Terramar 1.0 Trailhead CS Lightweight Long Sleeve 1/2 Zip Shirt- Men's 100% Polyester ClimaSense Thermoregulation Technology keeps you comfortable in all conditions - Engineered to adjust to your body temperature - Inhibits the growth of bacteria that causes odor - Fast wicking and drying Digital air pockets enhance moisture management and breathability Lightweight warmth (1.0) makes Trailhead extremely versatile Flat seam construction and dropped back tail for better fit UPF Rating 25+