Blue saphhire ball made from synthetic corundum produced using the Hydrothermal Synthesis Process and precision ground to 3.175mm in diameter.
 
     Dimension: ϕ 1/8" (3.175mm) +/- 2.54 μm 
     Sphericity: < 0.0006 mm (0.6 μm) 
     Roughness: Ra < 0.05 μm 
     Grade G25