... made of full ceramic material: ZrO2, SisN4 and Sic as a standard structure, the cage made of PTFE, GFRPA66-25, PEEK etc.All kinds of ceramic ball bearing ... , SiC and Al2O3, etc.Part of the model have in stock. Such as: 606, 607,608, 6205, 6800..... 606/607/608 Full Ceramic Ball Bearing&Ceramic Bearing