52100 Chromium Steel Sphere, Grade G25, Unpolished (Mill) Finish, Precision Tolerance, A295, 0.75" Diameter, 0.000024" Sphericity (Pack of 10) 52100 alloy steel provides high strength, high resistance to corrosion and wear, and good machinability Meets A295 specifications Meets grade 25 sphere tolerance Unpolished (mill) surface has No finish Precision tolerance