Generally, steatite ceramic material had the good performance in resist high temperature. The material cost was lower than Alumina material. But this material was more sensitive for temperature, so the parts made in this material, generally the tolerance can reach +/-0.25. The alumina material was more stalbe and density, and good ability in resist high temperature, but the cost was more higher. Generally, the steatite material was the reasonable material, which can be used in plug and ceramic blocks.