Drilax &reg; 10 Pcs Diamond Drill Bit Set 5/32", 3/16", 1/4", 5/16", 3/8", 1/2" , 5/8" , 3/4" , 7/8" , 1" In Inch Tiles, Glass, Fish Tanks, Marble, Granite, Ceramic, Porcelain, Bottles Lot Coated Bits DIY Kitchen, Bathroom, Shower, Lamps 100425 GREAT SET with 10 Mostly Used Sizes: from 5/32" in to 1 inch HUGE 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. Use a guide Tiles, Glass, Fish Tanks, Marble, Granite, Ceramic, Porcelain, Bottles FOR ALL DRILLS - HAND - PORTABLE - UPRIGHT - Shank sizes vary, maximum shank is 3/8