TechKewl Hybrid Cooling Vest Front zipperw/mesh ventilation panels and scoop neck Comfortable, quilted nylon outer with HyperKewlfabric inner, water-repellant nylon liner and black cotton-poly elastic trim Hybrid Cooling, Uses both Evaporative Cooling HyperKewl Fabric and Removable Phase Change Cooling Packs Include one (1) set ofCool Pax Phase Change Cooling Military Vest Inserts (7065 w/velcro) and protective cooler bag Will Not Swell or Bulge, Will not become slimy or leak toxic chemicals