The N-Ferno 6852 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 shoulder-length to keep head, ears and neck 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 a comfortable all-day fit. 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. 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.