Designed to be 30% to 60% lighter weight than other cooling vests on the market, the Chill-Its Lightweight Phase Change Cooling Vest keeps workers cooler, safer and more productive. Its 100% biodegradable phase change cooling material maintains a 59 deg F/15 deg C temperature for up to two hr when activated. Constructed with 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 cell phones and other small accessories. Sizing - The cooling vest comes in two sizes ranging from S/M (32 in to 40 in/81 cm to 102 cm) to L/XL (40 in to 52 in/102 cm to 132 cm). To find your size, wrap a tape measure around the widest part of your chest, under your arms, and completely around your torso. See size chart for more information. How to use Phase Change Cooling Packs not included. There are many ways to activate your cooling vest. Simply place the four removable packs in a cooler of ice water for 5 min, freezer for 8 min, refrigerator for 12 min, or near an air conditioner for 1 hr. Then place the recharged cooling packs in the vest pockets for hr of cooling. How to clean - The cooling pack should be washed by hand with a mild detergent and warm water. Dry with a paper towel or cloth. DO NOT machine wash or machine dry. The fabric vest is machine washable with mild soap, hang dry. This body cooling vest is perfect for anyone in need of instant cooling relief while working or playing outside or indoors in warm temperatures where heat-related illnesses like heat cramps, heat strokes, heat exhaustion, etc. are possible. Ideal for workers in pulp/paper, iron/steel, vulcanizing, foundries, etc. or for people running, biking, doing yard work, riding motorcycle and more. Also, ideal for those needing cooling relief but aren't able to use an evaporative cooling option.