1/2" Inch Diamond Drill Bit Hole Saw for Tile Glass Marble Granite Fiberglass Ceramic Tool (5 Pack) Diamond coating maximizes performance and retains a sharper cutting edge than traditional carbide or bimetal hole saws Side holes allow for easy slug removal after drilling Perfect set for cutting accurate holes in a wide variety of materials such as glass and ceramics Nickel plating on these bits maximizes your tools life with great resistance to corrosion 5pcs 12mm 1/2" Inch