TechNiche Phase Change Front Zipper Cooling Lite Vest Powered by CoolPax CoolPax is our Phase Change Material (PCM) cooling technology. It uses a non-toxic carbon-based liquid that freezes at 58 F/14 C and remains at that temperature for up to 1 hour. Features: Scoop neck with zipper closure Elastic side panels allow for a snug fit with no strings or ties, thereby reducing the risk of catching or snagging Front pockets with zippered closure 100% Cotton vest, with mesh ventilation Includes one cooler bag and one set of four (4) 7065V CoolPax Cooling Inserts Deploy extra CoolPax Cooling Inserts to achieve continuous cooling Total Weight: 2kg/4.4lbs (including 7065V PCM Cooling Inserts) Insert Compatibility: 7065V How to use: 1. Simply place CoolPax inserts in freezer or ice water for 35/40 minutes. 2. Insert activated CoolPax into garment pockets. 3. Your CoolPax item is ready to wear. CoolPax Inserts: Polyurethane Outer Material. Phase Change Material: 58 F Activation: Ice Water or Refrigerator Activated Duration: up to 2 hours TechNiche TechKewl 6626-LT Phase Change Front Zipper Cooling Lite Vest