Nike Dri-FIT technology is an innovative polyester fabric designed to help keep you dry so you can more comfortably work harder, longer. Dri-FIT's unique high-performance microfiber construction supports the body’s natural cooling system by wicking away sweat and dispersing it across the fabric's surface to evaporate faster. Dri-FIT clothes are most effective as a base layer or on their own—direct contact with your body means you stay dryer. And Dri-FIT's sweat-managing properties are permanent for the life of the clothing. So go ahead—sweat.