The N-Ferno 6892 FR Winter Hard Hat Liner - 3-layer, Modacrylic/Cotton has 3 layers of insulation for extreme warmth. This lightweight thermal liner is shoulder-length to keep head, ears and neck covered and fits comfortably under helmets or hard hats without feeling too bulky. The fire-resistant outer shell and lining are made of 60% modacrylic cotton and 40% cotton twill blend to stand up to tough environments and meets requirements of performance specification ASTM F1506; classified CAT2 according to NFPA 70E. Arc-rated; ATPV rating of 27 cal/cm2. A mid-layer of 3M FR Thinsulate provides maximum warmth and protection in extremely cold environments. There are four hook and loop straps on the exterior of the liner designed to securely attach to the interior of a hard hat for versatile protection in extreme work environments.