The HyperKewl™ evaporative cooling material is a unique fabric that absorbs and slowly releases water through evaporation. We look at this process as "super-charging" the bodies natural cooling process, thereby protecting the wearer against heat stress. While other technologies are effective for pre and post cooling while you compete, HyperKewl™ works to cool you during the competition or strenuous activity. Simply soak in water for 1 to 2 min, gently squeeze out excess water and enjoy the cooling effect for 5 to 10 hr. Simple, fast and easy to use. PIP® EZ-Cool® Cooling Ranger Hat, Evaporative, Series: 396-EZ450LY, S/M Size, Hi-Viz Yellow, Cotton/HyperKewl™, 1 to 2 min Soaking, Drawstring Closure