CoolMax® makes sweat a non-issue. The specially-engineered DuPont fibers used in CoolMax® fabrics transport perspiration away from the body to the surface of the garment, where it can evaporate quickly. At the same time, the uniquely-shaped fibers provide great breathability, even when wet. The breathability (called air permeability by fabric techies) further enhances the thermoregulatory effect. You stay dry. You stay comfortable. And you have more energy and endurance. 100% Polyester. CoolMax® Extreme Fabric has a UV rating of 25. Provides excellent skin protection; blocks 95% of UV rays. Made in the USA.