Features: Size: 50mm. Suitable for stone, tile, ceramic, glass, etc. Center positioning drill bit helps to cut precise holes Long Service Life: Reduced 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 facilitate the entry of cooling water and the evacuation of drilling chips. 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. Not suitable for use on concrete or for depths greater than approximately 1/2 inch.Description: 1. Smooth and precise finish to lower cutting resistance and drilling pressure, increasing sharpness and water