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° F (18° C) temperature for up to 4 hours 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