The N-Ferno 6876 2-Layer FR Winter Hard Hat Liner w/ Mouthpiece Kit includes a winter hard hat liner with 2 layers of insulation and FR technology to meet ASTM F1506 and also a thermal mouthpiece attachment for full-face coverage. The 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. Both the N-Ferno 6882 FR Hard Hat Thermal Liner and N-Ferno 6872 FR Thermal Mouthpiece have a fire-resistant outer shell and lining 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 20 cal/cm2. HARD HAT LINER There are 4 hook & 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.