Stay cool with the HyperKewl Evaporative Cooling Skull Cap from Techniche International. Made of 100% Polyester Mesh with HyperKewl Polymer embedded fabric in band around head. Just submerge in water 1 to 2 minutes to activate cooling. Stays cool for hours. Hand washable and hang to dry. Evaporative cooling products work best in dry climates, in humid climates you may need to rehydrate with cool water more frequently.