... of the line core bits for various types of stone Drill: Step Drill Core Bit for Water Drilling:-Fast, clean and efficient ... (3). Diamond grit: D427, D252, D181 and cutting thickness upon coating grit (4). Custom steel cores available upon request (5). Optional ... hang bag; Blister; or as your requirement (6). Used to drill marble, ceramics, porcelain, tile, glass, fiberglass, quartz, bricks, and a ...