The Chill-Its Lightweight + Rechargeable Phase Change Cooling 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 packs maintain a 64° F (18° C) temperature for up to 2 hours when activated. These packs are designed to be 30%-60% lighter weight than other cooling vests on the market. *** Phase Change Packs only, Lightweight Vest sold separately *** Visit