The Chill-Its 6230 Standard Phase Change Cooling Vest is made to house phase change cooling packs to keep workers cooler, safer and more productive. The phase change cooling material maintains a 64 deg F (18 deg C) temperature for up to 4 hr when activated. Made of a comfortable cotton blend fabric, this vest features adjustable hook and loop closures at the shoulders and waist to provide a customized comfortable fit. 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 - There are many ways to activate your cooling vest. Simply place the two removable packs in a cooler of ice water for 10 min, freezer for 15 min, refrigerator for 25 min, or near an air conditioner for 1 to 2 hr. Then place the recharged cooling packs in the vest pockets for hr of cooling. How to Clean - The fabric vest carrier 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.