... High precision & quality 2.ISO 9001 certified 3.Low noise,Stable in chemical 4.Single & double row Double row ball bearingMaterial: chrome ... 0.25≤0.25≤0.3 GCr15 bearing steel compare to same standard code: ChinaISOAISIDINJISSKFGCr15693/XVII52100100Cr6SUJ2SKF3Comparison Sheet for Bearing Precision ... seriesSpecification:1) Open, Z, ZZ, RZ,2RZ,RS, 2RS 2) Clearance: C0, C2, C3 3) Precision Tolerance: ABEC-1 ...