10.3 oz. Gray Cement & Mortar Cartridge. It is specifically designed for repairing cracked and chipped firebrick, as well as tuck pointing mortar into damaged masonry-to-masonry joints. This durable cartridge withstands temperatures up to 1093 °C (2000 °F) when heat cured, meeting the TM136-79 flammability test. Its non-asbestos formula ensures great bonding strength, making it ideal for repairing cracks up to 1/4 inch.