Light AND Cool Coverage. Stay covered on your runs with the Nike Dri-FIT Aerobill Featherlight Cap. Its ventilated design provides cooling, while an adjustable back strap allows you to choose your fit. This product is made with at least 50% recycled polyester fibres. Nike Aerobill technology integrates proprietary lightweight construction with breathable, sweat-wicking fabric for enhanced comfort and reduced distraction. Perforations throughout the cap help keep you cool. Adjustable back strap lets you customise the fit. More Details: Not intended for use as Personal Protective Equipment (Ppe). 100% polyester. 100% Polyester.