CUSTOMIZABLE COMFORT FOR A PERFECT FIT. The black underbill on the Nike Featherlight Cap helps reduce glare so you can see more and squint less. Sweat-wicking fabric and mesh inserts help keep you feeling cool and comfortable throughout the day. Benefits Nike AeroBill technology combines breathability with sweat-wicking comfort. Mesh panels enhance breathability. Back closure adjusts for a customized fit. 100% Polyester Imported Back Strap closure Hand Wash Only 100% polyester Hand wash Imported