Designed to be thirty to sixty percent lighter weight than other cooling vests on the market, the Chill-Its Lightweight Phase Change Cooling Vest helps to keep workers cooler, safer and more productive. Phase change cooling material maintains a 64°F\/18°C temperature for up to two hours when activated. Constructed of a polyester cotton blend fabric, the vest's adjustable hook-and-loop closures around the waist provide a customized fit for different body types. The heavy-duty front zipper makes for easy on\/off, while the two front zippered pockets can be used to store small accessories. Simply place the four removable packs in a cooler of ice water for five minutes, freezer for eight minutes, refrigerator for 12 minutes, or near an air conditioner for one hour. The cooling pack should be washed by hand with a mild detergent and warm water. Do not machine wash or machine dry. The fabric vest is hand washable with mild soap.