Carhartt FR resists flash fire and arc flash but never hard work. Built from 8.5-ounce, FR canvas: 88 percent cotton, 12 percent FR nylon, this vest offers two large front pockets, two inside pockets, the Carhartt FR label and HRC 4 label sewn on left pocket and it meets the performance requirements of NFPA 70e standards and is up classified to NFPA 2112.