Diamond Coating & Nickel Alloy Surface Nike - Diamond coating can increase the drilling speed and make the drill bit sharper; nickel plated surface can extend the service life and improve the corrosion resistance of the surface; thickened diamond coating on the top can provide excellent cutting force to achieve maximum drilling effect. 16Pcs Diamond Hole Saw - Comes with 16pcs drill bits in different sizes, including 6/8/10/12/14/16/18/20/22/25/28/30/35/40/45/50mm. Laser marking, the size will be clearer than other sizes and not easy to wear. Application - Suitable for drilling holes in glass, marble, ceramic tiles, block pots, fiberglass tiles, slate marble, lightweight granite, etc. Will be used with all electric drills and impact drills. Side Hole Opening & Laser Marking - Side hole design, the drill bit can eliminate waste and keep the drill bit clean; laser marking, the size mark is clearer and more durable than others, not easy to wear.