1.Precision: ABEC-3, ABEC-5, ABEC-7 2,Vibration level ... , 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 ...