1. Chrome Steel Ball (AISI25100,SUJ-2,Gcr15,100Cr6) 2.Size: 0.5mm-50.8mm 3.Grade: G10-G1000 4.Hardness: HRC61-66. 5.General Application: Bearings,Automotive,Castors,,Welding,Capabilities decorative,bicycle parts,light-duty,hardware,toy and etc.