Stay cool and safe in our Evaporative Safety Vest (ESV). Water causes a naturally cooling effect as it evaporates; these garments are made of a special fabric which holds the cooling energy for an extended period of time. Evaporative Cooling Safety Vest (ESV) is activated by simply submersing it in water for 1 to 3 minutes, or until it reaches the desired level of hydration. Gently wring out excess water and it's ready to wear! No freezers or cold packs necessary. Once activated, the vest will provide many hours of cooling relief. Evaporative cooling is especially effective in low humidity climates. Lightweight, unisex design with a zipper-pull front. Color: High Visibility Lime. Available in S, M, L, XL, XXL. Fitted vest is not adjustable.