Flue Goo is a multi-purpose furnace-refractory cement. It will bond masonry to masonry steel to steel and steel to masonry. Flue Goo will withstand temperatures up to 3000 Degrees F without cracking or shrinking. On the other end of the temperature spectrum Flue Goo is freeze-thaw stable however it is still a good idea to bring it indoors in freezing weather. Flue Goo contains no asbestos. It comes premixed and ready to use and is water-soluble for easy cleanup. Color Gray – .5 gallon container. It is not for exterior use.