Usage Tips:Great for cutting gemstones, glass, porcelain, tile, carbide, rock, ceramic, aluminum and copper, great for crafts, hobbies, home repairs, jewelry, gem use, modeling, and more.The diamond grinding head set features a 3 mm (1/8 in.) shank grinding head that is compatible with most rotary tool or die grinders.The cutting wheels diameters are 20mm and 30mm, the impellers are 12mm and 15mm, the Mandrel Diameter is 3mmColor as shownMaterial: diamondPackage Contents:26 x diamond burr bits4 x diamond cutting wheels3 x metal Mandrel10 x impellersOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.