The Onyx Cool Knee features a plant-based phase change material that cools to a skin-safe and soothing 58 degrees – the doctor-recommended temperature for cool therapy. This form-fitting, cooling compression wrap is anatomically designed for active recovery-so you can stay in the game or wear during rest and recovery. This cool (not too cold) device is safe to wear directly on the skin without risk of ice burn, frost bite or vasoconstriction. Cooling PCM safely permeates tissues to relieve pain and draw heat and inflammation away. Maintains constant 58 degrees cooling for about an hour. Latex free. To clean, wash with mild soap and water then air dry.