The Chill-Its Lightweight Phase Change Cooling Vest Packs are made to be inserted into model 6255 Lightweight Phase Change Cooling Vest to keep workers cooler, safer and more productive. The phase change cooling material in the packs is 100% biodegradable and maintain a 59 deg F (15 deg C) temperature for up to 2 hr when activated. These packs are designed to be 30%-60% lighter weight than other cooling vests on the market. 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 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. 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.