... :1,ABEC-3,5;Z2V2,Z3V3 2,High speed 3,End cover:ZZ,RS 4,Noise level:Z1,Z2 5,C2 ... are devided into two ends of perforation(HK-type) and closed end bearings(BK-type).Drawn Cup Needle Rpller Bearings seal one ... end of a closed structure,applicable to shaft end and can withstand small Axial momentum.HKPiercing ...