RefrigiWear's CoolZone personal cooling system is comprised of the CoolZone Carrier Vest/102 and the CoolZone Phase Change UniPak/102-PK, designed to reduce the dangers of heat stress for workers in extremely warm environments. The system uses phase-change technology to provide an average of three to five hours of effective relief from the heat. As the cooling material in the UniPack absorbs excess body heat, it cools the blood and surrounding tissue regulating and stabilizing the user's internal temperature. The vest is constructed of quilted 200 denier nylon and features adjustable side and shoulder straps.