8" OD, 46-2000 Grits for Choice, Flat Lap Disc Wheel with Quality Electroplated Diamond Coating. Outer Diameter: 200mm; Thickness: Approx. 1.2mm; Arbor Hole: Approx. 12.7mm. They are absolutely flat and parallel to meet the most demanding requirements. Applications: For wide use of jade, crystal, agate, arts and crafts, gemstones, glass products, electronic tubes, crystal, precision machining and other industries. Recommended for rough and fine grinding on faceting material and general lapidary grinding where precision is required.