1)Diameter/Size: 3.969 mm 2)Grade: G1000 3)Hardness: 58-64HRC 4)Material: GCr15/AISI52100 stainless steel ball steel ball, bearing steel ball and stainless steel ball,the following is our specficspecifications:material:AISI 1008,1010,1015,1045,1055,1065,1085,AISI 52100,AISI 304,316,420,440,420C,440CSIZE:0.5-50.8mmGrade:G5.G10.G20.G40.G80.G100.G200.G500.G1000.G2000Packing:gross,bag,carton or ...