small ball bearings:1,ABEC-3,5;Z2V2,Z3V3 2,High speed 3, ... 5,C2,C0,C3... Features:1),Shield / closure: Open,Teflon Sealed,Rubber Seals,2 Metal Shield2),Tolerance codes: ABEC-1, ABEC-3 ... , C4, C55),Material: AISI52100, AISI440C, AISI304, AISI316, Ceramic6),Retainer: PTFE, Nylon, PEEK Or Stainless Steel7),Bore Size:from 3mm to 10mm8 ...