Drilax&trade; 10 Pcs Diamond Drill Bit Set Hole Saws for Kitchen, Bathroom, Shower, Faucet Wet Drilling Tool Ceramic, Porcelain Tiles, Glass, Marble, Granite Hole Sizes 1/4", 3/8", 1/2" (0.5 Inch) , 3/4" , 1", 1 1/4", 1 3/8", 1 1/2", 1 3/4", 2" Diamond Drill Bit Tools 10 pcs Set 1/4, 3/8, 1/2, 3/4, 1, 1 1/4, 1 3/8, 1 1/2, 1 3/4, 2 Best value set in durable zipper case. Great gift idea for any DIY lover. There is no need for a center pilot drill. These tools do not have center pilot drills. Diamond Coated Tools will work best if you use water to keep the tools cool. Pleasedo NOT run dry. Shank size is 3/8 - suitable for all common electric drillers. Max depth 1 inch.