The Black Stallion B-WFG18 18 oz. Heat Cleaned Fiberglass offers excellent heat resistance. Fiberglass offers excellent heat resistance and resists melting up to 1,000°F. The B-WFG18 is made with Tan 18 oz. heat cleaned fiberglass and is .033" thick. Finished blankets include grommets on all sides, making this ideal for LIGHT DUTY applications: light sparks and spatter.