HyperKewl 6538-S/M-HV Evaporative Cooling Vest 60% HyperKewl,40%Nylon Imported Uses Hyperkewl Fabric to cool for 5-10 hours Comfortable V-neck oversized cut with Pockets Full ANSI Class II Compliant with HiVis colors and Reflective Striping No slimy residue or swelling gel or crunchy chemicals Many Size and Color Options