14Pcs set 3-70mm Drill Bits Coated Hole Saw Cutter for Glass Porcelain Tiles Marble, Granite,Hole Saw : We strive to provide you with high quality and convenient service. You are welcome to us if you have any problem about our product, we will give you a satisfactory reply. This section openings optimum glass openings, tiles can be opened, but only open a few holes in the opening, please add water, it will extend the life. This bits are installed on a professional drill or electric drill, bench drill. Rpm 800-1000 rpm or so, you must add water cooling holes during. Features: High quality and Brand new. This product uses advanced material, with a special enhanced coagulation treatment from electroplating sand suction hole neat, smooth, no broken edges, etc., is the efficient construction, installation hole of choice. This section openings optimum glass openings, tiles can be opened, but only open a few holes in the opening, please add water, it will extend the life. The product is installed on a professional drill or electric drill, bench drill. Rpm 800-1000 rpm or so, you must add water cooling holes during. Use: apply to job openings fast glass, plastic sheeting, wood and other products. Size: 3mm / 5mm / 6mm / 8mm / 10mm / 12mm / 16mm / 18mm / 20mm / 30mm / 40mm / 50mm / 60mm / 70mm Package Includes: 14pcs Coated Hole Saw Drill Bits NOTE: 1 After opening installation, commissioning idling should observe whether the beating, then normal, the best results 2 Into the hole to have a smooth time, please do not exert pressure on the side and curves spud 3 Have enough openings for cooling and lubrication to reduce wear and coating products off 4 Non-occurrence of high-temperature drilling dry rub, causing severe wear affect the results 5 The operator must wear safety protective equipment to ensure