high precision and long life Seal form: open style, Z, ZZ, RS, 2RS, 2RZBearing stop ring: N,NRClass of precision: ABEC-1, ABEC-3, ABEC-5, ABEC-7 Vibration rank: V1, V2, V3, V4 Noise rank: Z1,Z2,Z3,Z465.Internal elimination code: C0, C2, C3, C4, C5Bearing material: bearing steel (9Cr18), stainless steel(AISI440C, AISI304, AISI316), ceramics Keeper: stainless steel, PTFE, nylon Bearing ferrule and ...