Refractory sheet board type RS-100 is a ceramic-fiber-reinforced structural alumina composite material with useful properties to 1260°C (2300°F). It has exceptional flexural and compressive strengths in the range of high-temperature reinforced plastics and retains strength and utility to levels far exceeding maximum use temperatures of plastics. The mechanical properties of type RS-100 sheet far exceed those of Transite and other asbestos-cement materials. As such, type RS-100 is an excellent replacement for these rigid asbestos-containing products, and it can also be employed at much higher temperatures than these types of products. Type RS-100 is 100% inorganic, non-flammable and contains no asbestos. Its high Al2O3 content makes it highly resistant to many environments, including molten aluminum. Type RS-100 undergoes little or no outgassing on heating, and it can be cut and machined with standard tooling.