50+ Ultraviolet Sun Protection Factor (UPF)This fabric does an excellent job at the disruption of ultraviolet light. The fabric is woven with advanced nylon micro fibers that have a hydrogen and carbon based benzene ring in the polymer. The fibers are extruded and coated before being spun into yarns.All fabrics will protect from the sun"s UV radiation to some extent. The type of fabric that does the best job at blocking harmful sun rays will carry a Ultraviolet Protection Factor (UPF) rating from 15 (good) to 50+(excellent).Wetness: The desire to keep out the sun"s UV rays is reduced by wetness on the fabric. A wet fabric may cause the sun blocking to be reduced by up to half its effectiveness as dry. Keeping the fabric dry is enhanced by the durable water resistant finish. The DWR finish creates a fabric that is lightweight and hydrophobic. The dense, tight woven microfibers minimize the space between yarns. This reduces the amount of UV light that can pass through which leads to the 50 UPV score.