... bearings :1,ABEC-3,5;Z2V2,Z3V3 2,High speed 3,End cover:ZZ,RS 4,Noise ... ),Shield / closure: Open,Teflon Sealed,Rubber Seals,2 Metal Shield2),Tolerance codes: ABEC-1, ABEC-3, ABEC- ... 30mmCurrently, our miniature bearings contains the following types, Metal Shield Bearings Open Bearings Rubber Seals Bearings Teflon ... Hybrid Ceramic Bearings Hybrid Ceramic Bearings High Performance miniture bearings