The N-Ferno 2-Layer Thermal FR Mouthpiece for Hard Hat Liners features layers of insulation with a modacrylic/cotton blend shell and liner to provide comfort, warmth and face protection in extremely cold weather work conditions. This thermal winter face mask is made to fit most N-Ferno Winter Liners (liners sold separately) to double up the warmth on those frigid jobsites. FR rated materials meet ASTM F1506 and are classified to CAT 2 according to NFPA 70E. Great cold weather work gear for people who spend extended periods of time in cold environments and need such as construction, freight, drilling or mining, delivery service, landscaping, and warehousing. This thermal mouthpiece is also great for recreational use like skiing, snowboarding, sledding or other winter activities that may need a helmet.