... material:bearing steel,GCR15 hardness:59-63HRC 16001 2rs low noise deep groove ball bearing detail description:1) Types: ... ), Z, ZZ, RS, 2RS, 2ZR, 2Z. 5) Vibration and Noisy level: Z1, Z2, Z3, ZV1, ZV2.ZV3.Z1V1.Z2V2.Z3V3. ... 6) Precision level: ABEC-1, ABEC-3, ABEC-5, ABEC-7. 7) ... establish friendly relations of cooperation. 16001 2rs low noise deep groove ball bearing