The Ergodyne Chill-Its 6715CT Evaporative Cooling Hard Hat Pad straps into hard hats to deliver 4 hours of cooling relief. The low-profile and lightweight liner pad features advanced PVA cooling technology for instant cooling without bulk or slime, making it comfortable to wear under hard hats. This hard hat liner pad fits most hard hats and safety helmets, easily and securely attaching to the suspension with 2 hook loop straps. Heat-related illness continuously ranks among the top causes of worksite accidents and fatalities. Evaporative cooling technologies such as PVA 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 PVA cooling hard hat pad is comfortable and refreshing for even the hottest days of the year. The cooling hard hat pad activates in seconds, just run it under water for 1 minute to activate instant cooling relief that lasts for up to 4 hours. The PVA will retain water without bulk or residue. Machine wash as needed and hang to dry. Note that PVA materials stiffen as they dry. Simply run under water to reactivate and soften. Ideal for construction, telecommunications, or anyone wearing head protection while working in the heat!