The N-Ferno 6867 Winter Hard Hat Liner has 3 layers of insulation with a quilted polyester shell, a foam mid-layer and a thermal polyester fleece lining. 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. There are four 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