... certified 3.Low noise,Stable in chemical 4.Single & double row Double row ball bearingMaterial: chrome steel STEEL NO.COMPONENTCSiMnCrMoPS CuNiGCr150.95 ... , Inch R series,MR Series,RLS series,RMS seriesSpecification:1) Open, Z, ZZ, RZ,2RZ,RS, 2RS 2) Clearance: C0, C2 ...