High Quality Diamond Drill Bit Set No Rust, Fast Cutting - Made from high strength carbon steel with nickel plated surface makes these drill bits durable and precise; the drill bit tip head is made of 80 grit diamond coating, which is uniform; it helps to increase drilling speed and sharper than other ordinary hole saws. 10 Pcs Most Used Size - Includes the following diameters: 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 50mm. Using laser marking, the size will meet most of your different needs. Application: Suitable for drilling holes on glass, marble, tile, pots, fiberglass, porcelain, tile, ceramic, slate, granite, etc. Works with all electric drills and impact drills. Nice Design - Center holes and side holes help remove waste easily; Nickel-plated surface extends service life and improves corrosion resistance Notice: When cutting hard materials, it is important to ensure that the cutter remains cool to avoid damage to the material being drilled and premature wear of the