... : G100, G200, G500.G1000,G2000 3.material : AISI1020 Material ASTM/AISI 1020Feature:High hardness with a soft core giving resistance to ... slides, seat slides, bicycles, etc.CertificationISO 9002: 2000OriginalShandong province , China AISI 1020 LOW CARBON STEEL BALL (0.5MM-100MM)