ZWZ Bearing ZWZ Bearing is the best bearing in China ZWZ BearingZWZ Bearing is the best bearing in China.It is included: ... Bearingand other kinds of types1. Seal form: open style, Z, ZZ, RS, 2RS, 2RZ2. Bearing stop ring: N,NR 3 ... , C57. Bearing material: bearing steel (9Cr18),stainless steel(AISI440C, AISI304, AISI316), ceramics8. Keeper: stainless steel, PTFE, nylon9. Bearing ferrule and ball hardness ...