The Chill-Its 6700CT Cooling Bandana features polymer crystal cooling technology for relief in extreme heat. Lightweight and low-profile, this comfortable cotton bandana is perfect for wear around the neck or under hard hats. A tie closure in the back makes for an adjustable, snug fit on a variety of head sizes. Polymer crystals are a simple, effective and comfortable solution for heat stress prevention. Similar to how sweat cools the body, evaporative technologies use an external water source to draw heat away” helping to regulate body temperature while providing cool relief. When activated, this cooling head wrap is comfortable and refreshing for even the hottest days of the year. HOW TO ACTIVATE Soak in water for 2-5 minutes to activate. The embedded polymer crystals will retain water for up to four hours of cooling relief. Be careful not to over activate as that may cause the bandana too plump up to a size where it is no longer able to be comfortably worn.