3/16" Inch 4.9 mm DiamondSure Diamond Drill Bit Hole Saw for Glass, Tile, Granite, Ceramic, Porcelain, Stone DiamondSure bonded diamond core drill bits cut through materials where other bits fail. They are electroplated DiamondSure bits can be used in any standard variable speed drill designed for drilling to depths of about 1/2" in ceramic tile Not designed for use on concrete, masonry, metal or for use with impact hammer drills.