The N-Ferno 6871 2-Layer Winter Hard Hat Liner with Mouthpiece Kit includes a winter hard hat liner with two layers of insulation and 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 6852 Hard Hat Thermal Liner and the N-Ferno 6870 Thermal Mouthpiece have a breathable 100% cotton twill outer shell and a soft 100% polyester fleece lining for added comfort and to stand up to tough environments. 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 contains pockets by the ears designed to hold regular-sized hand warmers (sold separately) to keep ears warm and comfortable in extreme temperatures.