Kishigo Brisk Cooling Series® Bandana Tie ul)Provides extended cooling comfort and heat stress prevention. Can be tied around neck or head. Powered by HyperKewl™ Evaporative Cooling Technology. Lightweight, durable and reusable. To activate simply submerge in water for 2-3 minutes. EVAPORATIVE COOLING TECHNOLOGYSpecialized fabrics and fibers create an advanced water management system, called ‘HyperKewl’.HyperKewl absorbs, stores and releases water within the multi-layered structure.The fabrics cool itself through evaporation and a chill effect is created.Users can expect the evaporative cooling fabric to provide temperatures that are up to 15-20degree cooler than the ambient temperature.Fabric dye lot variances may occur and meet luminance factor as stated in the standard.