... executions and sizes. Features: Shield / closure: Open ball bearing, Z, ZZ, RS, 2RS, 2RZ Ball bearings snap ring: N, NR Tolerance ... level codes: V3, V2, V1 Internal clearance codes: C2, C0, C3, C4Ball bearings material: AISI52100Retainer: PTFE, nylon, or stainless steel Hardness ... .536.0600070000.783 Industrial ball bearings(6201,6202,6203,6204,6205)