The Chill-Its 6715 Evaporative Cooling Hard Hat Cooling Pad straps into hard hats to deliver four hours of cooling relief. The low-profile and lightweight liner pad features cooling acrylic polymers for instant cooling without bulk or slime, making it comfortable to wear under hard hats. This hard hat liner fits most hard hats and safety helmets, easily and securely attaching to the suspension with two hook & loop straps. Heat-related illness continuously ranks among the top causes of worksite accidents and fatalities. Evaporative cooling technologies such as 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 hard hat pad is comfortable and refreshing for even the hottest days of the year.HOW TO ACTIVATESoak in water for 2-5 minutes to activate. The polymer crystals will retain water for up to four hours of cooling relief. Be careful not to over activate as that may cause the liner pad to “plump up” to a size where it is no longer able to be comfortably worn. To reactivate cooling, simply re-wet. Ideal for construction, telecommunications or anyone wearing head protection while working in the heat.