Grade: 25 Material: Chrome Steel (AISI 52100) Diameter: 7/16" Inches (11.1125 millimeters) Weight: 0.1989 ounces (5.64 grams) PGN’s G25 7/16" Chrome Steel Balls extremely precise and smooth surface guarantees you won't find any defects, such as flats, pits, soft spots, and cuts.