Stay Warm - PREMIUM Flame Resistant Hard Hat Tube Liner - Nomex - EACH Comfortable with maximum stretch. 8.75 oz. Nomex Rib Knit. Meets ASTM F1506. Arc Rating: ATPV = 7.8 cal/cm. NFPA 70E / HRC = 1. Fits snugly over most regular brim hard hats. Flame resistant through the life of the garment.