High Quality Diamond Drill Bit Set - Made of high strength carbon steel with a nickel plating surface, these drill bits are durable and precise; The bit head is made of an 80 grit diamond coating, which is uniform; It helps a lot in increasing the speed of drilling and is sharper than other regular hole saws. 10 Size - 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 50mm; Using laser marking, the size will meet most of your needs. Application - Suitable for use in drill holes on glass, marble, tiles, jars, ceramics, ceramics, granite stone, stone, etc. Design - Center pilot holes and side holes help remove waste easily; and nickel plating of the surface, extend the service life, improve the corrosion resistance of the surface Notification Kind - When cutting hard materials, it is important to ensure that the cutter is kept cool to avoid damage to the drilled material and premature wear of the cutter; When drilling, water is needed for lubrication, which can extend the life of the drill bit.