... ,electric tools,power tools,sports apparatus,machines, etc 1- thin ball bearings feature:68,69series with open,Z,ZZ,RS,2RS,NR ... available2.material:chrome steel3.quality certification:ISO9001:2000 system4.vibration and noise level:Z1V1,Z2V2,Z3V35.precision level:P0,P6,P5 ... available7.Advantage:competitive prices with excellent quality High Quality Thin Ball Bearings (68series)