Grade: 25 Material: Chrome Steel (AISI 52100) Diameter: 3/16" Inches (4.7625 millimeters) Weight: 0.01566 ounces (0.44398 grams) PGN’s G25 3/16" Chrome Steel Balls extremely precise and smooth surface guarantees you won't find any defects, such as flats, pits, soft spots, and cuts.