Shield / closure: open ball bearing, z, zz, rs, 2rs, 2rz Ball bearings snap ring: n, nr Tolerance codes: abec-1, abec-3, abec-5, abec-7 Vibration level codes: v4, v3, v2, v1 Internal clearance codes: c2, c3, c4, c5 Ball bearings material: aisi52100, aisi440c, aisi304, aisi316, ceramic Retainer: ptfe, nylon, peek or stainless steel Hardness for rings and balls: 59 - 63hrc Ball bearings bore size: 1 - 200mm Versions: Ball bearings with one or two side rubber seal rs, 2rs With one or two side metal shields z and zz (2z) With a snap ring groove in outer ring n With a snap ring groove in outer ring and external snap ring nr In different radial clearances c5, c4, c3, c2. Applications : Typical applications: electric motors, automotive applications, home appliances, industrial equipment. It depend on your requirement