Black Silicone Nitride ball made using the Gas Pressure Sintered (GPS) 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