Nike AeroBill Featherlight Unisex Tennis Hat sets you up with sweat-wicking Nike AeroBill technology, an adjustable closure and perforated vents_an ideal combination for staying cool and comfortable on and off the court. Nike AeroBill technology combines breathability with sweat-wicking comfort. Adjustable closure provides a customizable fit. Terry sweatband is soft and absorbent. Laser perforations help enhance breathability. Fleece fabric has a heathered look and a soft feel.