HyperKewl 6530-HV-M Evaporative Cooling Vest , Hi-Visibility Lime 60% HyperKewl,40%Nylon Imported Uses Hyperkewl Fabric to cool for 5-10 hours Comfortable Crew Neck style with full zipper and two zipper pockets Will not bulge or change in fit or appearance No slimy residue or swelling gel or crunchy chemicals Many Size and Color Options