Product specifications: 5.9mm/6mm/6.35mm/6.5mm/6.6mm/6.747mm/6.8mm/7.144mm/7.938mm/8.1mm/8.731mm/9.525mmQuantityGcr15 material, solid precision bearing steel balls, high-precision wear-resistant and compression-resistant, smooth surface,bearing machinery is the best choice!The more commonly used uses of bearing steel balls: grinding, installation of equipment, machine wear, experiments, inspection of pipes, industrial balls, etc.