Features: Suitable for stone, tile, ceramic, glass, etc. Center positioning drill bit helps to cut precise holes Long Service Life: Lower drilling speed, low drilling pressure and increased use of water lubrication will extend the life of the drill bit Clearance Hole: Diamond drill bits with clearance hole make it easier for cooling water to enter and drill chips to escape. Makes the drilling process easier Clean and Smooth Cutting: Diamond hole saw creates high-precision smooth cuts without broken edges. White zinc plating on the bits maximizes tool life with excellent corrosion resistance Tips: Please use at low drilling speed and drilling pressure. Always work with coolant (water) when drilling. Not suitable for drilling tempered glass, plastic and wood.; Product Description Description: 1. Smooth and precise finish to lower the incision resistance and drilling pressure, increasing the sharpness and efficiency of water lubrication. 2. Produces clean and precise holes in minutes