1.Material: Gcr15 high carbon chrome bearing steel (AISI 52100)
  Grade:G5  
2.Size:2.0mm,2.381mm(3/32\),3.175mm(1/8\),3.5mm,3.969(5/32\),4.763mm(3/16\), 5.953mm(15/64\),6.35(1/4\)   
3.HRC:62-66    Noise: 26-30db