Knee pain relief patent: Knee cold support for the front and back of the knee adjustable compression and hot and cold treatment, effectively reduce swelling, pain and inflammation. Hot or Cold Treatment: Includes three removable Arctic Flex gel packs for hot or cold treatment. Breathable Neoprene Blend: Machine washable for added convenience, the knee wrap is made from a lightweight neoprene blend. Reheat every 10 seconds until the desired temperature is reached. On the stove, bring 3 quarts (3.5 L) of water to a boil. Remove the water from the heat source. Do not submerge the gel pack while the water is heating. Dip the gel pack in hot water for 2.5-3 minutes. How do I cool gel packs? Place the gel packs flat in the refrigerator for at least 2 hours. Remove the gel pack from the refrigerator and place it on your knee pad before using.