Thorzt Evaporative Cooling Slip-Over Vest CSOV (Each)This slimline pack is made from tough and durable lightweight materials with closed cell insulation that keeps water cool for hours. A cooler body improves the ability to sustain intensive workloads over longer periods of time. The THORZT evaporative cooling vests use the natural process of evaporation to help cool your body. A cooler body contributes to a number of physiological advantages: Delay the onset of dehydration Less output is directed