... operation 4.wide spreed use and versahty Ball BearingsProduct DescriptionProduct DescriptionMiniature ball bearings specifications: 1) Shield / closure: Open bearing, Z, ZZ, RS, 2RS 2 ... : C2, C3, C4, C5 6) Material: AISI52100, AISI440C, AISI304, AISI316, ceramic 7) Retainer: PTFE, nylon, PEEK or stainless steel 8) Bore ...