52100 Alloy Steel Ball, Material Alloy Steel, Material Grade 52100, Ball Bearing Grade 25, Ball Weight 11.937 g, Outside Diameter 9/16 in, Rockwell Hardness C60 to C67, Mechanical Finish Polished, Machinability Not Rated, Standards AISI E52100, Outside Diameter Tolerance +/-0.0001 in, Brinell Hardness 654, Application Automotive, Heat Treatable Yes, Heat Treatment Tempered, Shape Ball, System of Measurement Inch, Package Quantity 25