... 2.material is SSiC 3.full ceramic bearing 4.we are manufacturer SSiC:Usage: high precision,high speed,vacuum,fixed anode X-ray ... tube,high temp,low temp,electric insulation,high precision ballscrew set,valve balls for acid,alkali,salt,measure pumps ... gas of deleterious, especially resistance to hydrofluoric acid,long life,high hardness,resistance to wear. ceramic sleeve