One gallon of buff-colored fire clay, High temperature furnace/refractory cement that withstands up to 2700 degrees Fahrenheit, Pre-mixed in a heavy body, but with smooth consistency, Use to fill gaps and holes in masonry, for installation and repair of fireplaces, furnaces, wood or coal stoves and boilers, or preventing air and gas leaks in flue and chimney joints, Bonds metal to metal, masonry to masonry and masonry to metal, To obtain maximum hardness it is best if heat cured, SKU: RTLD318