1.Precision: ABEC-3, ABEC-5, ABEC-7 2,Vibration level codes:V3, V2, V1 3.Internal clearance codes:C0,C2, C3, C4, C5 1)Shield / closure: Open,Teflon Sealed,Rubber Seals,2 Metal Shield2)Tolerance codes: ABEC-1, ABEC-3, ABEC-5, ABEC-73)Vibration level codes: V4, V3, V2, V14)nternal clearance codes: C0,C2, C3, C4, C55)Material: AISI52100, AISI440C, AISI304, AISI316, Ceramic6)Retainer: PTFE, Nylon, ...