Rated for 500 Degree, Continuous and 600 Degree Intermittent. Recommended for sealing connections such as the tee & tee snout, rigid liner, etc... For gas / wood fireplaces, stoves, pellet burners, etc. Product expands and contracts as appliance heats up and cools down. Cures when heat is applied from the appliance. 10.3 oz. tube.