The N-Ferno 6850 Winter Hard Hat Liner has two layers of insulation with a cotton shell and a comfortable polyester fleece lining for exceptional warmth. This lightweight thermal liner is chin-length to keep head and ears covered and fits comfortably under helmets or hard hats without feeling too bulky. The outer shell is made with 100% cotton twill to stand up to tough environments. The 100% polyester fleece lining is soft to the touch for comfortable all-day wear. A hook and loop chin strap comfortably secures this winter liner, while four exterior hook and loop straps attach to the interior of a hard hat for a secure attachment and added warmth. This hard hat winter liner has an elastic strip in the forehead area to keep the liner snug against the face to trap body heat in and keep cold out. Small pockets by the ears are designed to hold regular-sized hand warmers (sold separately) to keep ears warm and comfortable in extreme temperatures.