The Ergodyne N-Ferno 6878 Winter Hard Hat Liner w/ Mouthpiece Kit includes a winter hard hat liner with 3 layers of extreme 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.The N-Ferno 6867 Hard Hat Thermal Liner has a 100% polyester quilted outer shell, a mid-layer of foam insulation to provide an additional layer of thermal protection and a soft 100% polyester fleece lining for extremely cold environments. The N-Ferno 6874 Thermal Mouthpiece has a breathable and water-resistant 1mm neoprene outer shell construction to trap heat in and a soft fleece liner for additional comfort.There are 4 hook & loop straps on the exterior of the liner designed to securely attach to the interior of a hard hat. This detachable face mask design allows you to let in air or remove for speaking when needed.