High-quality diamond drill bits with an economical and fast-cutting surface - These drill bits are made of high-strength, nickel-plated carbon steel and are durable and precise; the head end is made of a uniform 80-grit diamond coating; it greatly contributes to increasing the drilling speed and is sharper than other ordinary saws. 10 pieces, mainly used sizes - Includes the following diameters: 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm, 25 mm, 50 mm; Laser marking ensures the size meets most of your different needs. Application - Suitable for drilling holes in glass, marble, tiles, cement pots, fiberglass, porcelain and ceramic tiles, blva0299 slate, light granite, etc. Works with all electric drills and hammer drills. Beautiful Design - Center and side holes help easily remove waste materials; and the nickel-plated surface extends the service life and improves the surface's corrosion resistance. Notification Type - When cutting hard materials, care must be taken to keep