10.3 OZ, Gray, Cement & Mortar Cartridge, Especially Suited For Repairing Cracked & Chipped Firebrick & Tuck Pointing Mortar Into Damaged Masonry-To-Masonry Joints, Durable As Firebrick When Heat Cured, Withstands Temperatures Up 1093 Degrees Centimeter, 2,000 Degrees Fahrenheit, Meets A TM136-79 Flammability Test.