Maintains constant 64º F/18º C. Cooling lifecycle lasts up to four hours. Comfortable cotton construction with hook-and-loop closure. Extended vest surface area to enhance cooling power. Non-toxic, non carcinogenic substance. Features elastic pen loop and patented honeycomb pack design to provide improved flexibility. Modacrylic cotton blend FR fabric. Fabric meets ASTM F1506 performance requirements (ATPV rating of 7.1 cal/cm²); classified CAT1 per NFPA 70E. Hi-vis 6215HV version also available- orange with reflective accents.