Internal Combustion Engine Bearings1)Shield / closure: Open,Teflon Sealed,Rubber Seals,2 Metal Shield2)Tolerance codes: ABEC-1, ABEC-3, ABEC-53)Vibration level codes: V2, V14)nternal clearance codes: C0,C2, C3, C4, C55)Material: AISI52100, AISI440C, AISI304, AISI316, Ceramic6)Retainer: PTFE, Nylon, PEEK Or Stainless Steel Thin walled..