Drilax&trade; 3 Pcs Diamond Drill Bit Set 1/4" , 1/2" , 3/4" for Tiles, Glass, Fish Tanks, Marble, Granite, Ceramic, Porcelain, Bottles, Quartz, Lot 3 Diamond Coated Hole Saws- Kitchen, Bathroom, Shower, Faucet - Bottle Lamps - Wet Drilax030720 High Quality Diamond Drilling Tool Set of 3 Different Sizes: 1/4" 1/2" 3/4" - Most Used Sizes Over 80% cost savings compared to big box stores. Use with standard electric or battery drillers. There is no need for a center pilot drill. These tools do not have center pilot drills. Do NOT run dry. Diamond Coated Tools will work best if you use water to keep the tools cool. Shank sizes vary, maximum shank is 3/8" - suitable for all common electric drillers.