The stylish new Aero Bill Classic 99 Caps are equipped with Nike’s Dri-Fit technology, this provides a lightweight performance Cap with breathability & moisture wicking properties. These stunning caps have been designed using a blend of Polyester & Spandex, a fantastic combination that offers supreme comfort & high durability. A sweatband helps to eliminate any excess moisture & the Caps feature high-tech laser perforated side panels to enhance air-flow.