The Chill-Its 6702 Cooling Headband features evaporative cooling technology designed to deliver instant cooling relief lasting up to 4 hours. This lightweight headband is designed with polymer crystal technology embedded in a batting material for fast cooling without the bulk. Embedding the polymer crystals reduces uneven expansion of the polymers when wet (less bulk, more comfort). Use the tie-closure to adjust the fit around the head, neck or wrists. HOW TO ACTIVATE Simply