NRS HydroSilk is the perfect solo layer to wear when the weather gets warm and a great base layer in cold weather. The HydroSilk's new 8-oz. material will increase moisture wicking. The new 8-oz. nylon/spandex fabric improves moisture wicking to keep you more comfortable. HydroSilk has a UV protection rating of SPF 50, guarding your skin from the damaging effects of sunlight. Form-fitting design allows for unrestricted layering. A silky outside and soft-brushed inner feels great against the skin.