Cool Pax Phase Change Cooling Military Vest Inserts w/ Velcro Hook - Extra SetReplacement Inserts for TechNiche Hybrid Cooling Military Vest (7026, 7027, 7032) Includes: (4) Cool Pax\xBB Phase Change Cooling Inserts Unique "Buddy Swap" design for easy changing of inserts in the field 10,000+ units in operational use in the US Military Phase Change Cooling Inserts maintain a comfortable 58\xC1F (15\xC1C) for up to 3 hours Cool Pax Phase Change Cooling Military Vest Inserts w/ Velcro Hook - Extra Set