Ultra - The versatile Nike Fly cap accompanies you from warm-up to cool-down and everywhere in between. This shallow, structure -free model is made from breathable ultra-fabric incorporating advanced anti-perspirant technology for maximum freshness in all conditions. The back strap is also easy to adjust, so you can concentrate on what matters - achieving your sporting goals. - Nike Dri-FIT ADV technology combines anti-perspirant fabric with advanced innovations. You stay dry and enjoy total comfort. - Nike Aero - Bill technology combines breathability and anti-perspiration comfort for maximum concentration. - Four-way stretch twill fabric for a comfortable fit. - Velcro closure for easy customization. - Perforated front and side panels for enhanced breathability.