Phase Change Cooling Vests are designed with revolutionary phase change material (PCM) to keep the user cool. PCM is a non-toxic, carbon based liquid that has a high latent heat of fusion. It freezes at 58F and stays at that temperature for around 2-3 hrs. Phase change cooling vests get quickly activated in a refrigerator, freezer, or in ice water. They absorb heat from the body and keep the user cool and comfortable. As a matter of fact, they are cool vests, not cold vests. They will not cause any ice burn, condensation or temperature fluctuations. At Health Products For You, we offer a wide range of phase change material cooling vests from top-selling brands such as Polar, Glacier, and Techniche @ attractive prices.