The N-Ferno 6871 2-Layer Winter Hard Hat Liner w/ Mouthpiece Kit includes a winter hard hat liner with 2 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 sh