The Chill-Its 6230 Standard Phase Change Cooling Vest with Rechargeable Packs keeps 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. The vest is made of a comfortable cotton blend fabric with adjustable hook and loop closures at the shoulders and waist to provide a customized comfortable fit. Phase Change Packs and Vest are also available separately. SIZING