Grade: 25 Material: Chrome Steel (AISI 52100) Diameter: 1-1/2, 1.5 inches (38.1 millimeter) Weight: 8.018 ounces (227.3217 grams) PGN’s G25 1-1/2" Inch Chrome Steel Balls extremely precise and smooth surface guarantees you won't find any defects, such as flats, pits, soft spots, and cuts.