The N-Ferno 2-Layer Thermal Mouthpiece for Hard Hat Liners features layers of insulation with a cotton shell and a polyester fleece 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. Great cold weather work gear for people who spend extended periods of time in cold environments such as construction, freight, drilling or mining, delivery service, landscaping, and warehousing. This face cover is also great for recreational use like skiing, snowboarding, sledding or other winter activities that may need a helmet.