CNBTR 10mm Diamond Silver Hole Saw Drill Bit Set for Tile Ceramic Porcelain Glass Rock Pack of 10 Material: Alloy This diamond coated core drill bit removes a complete circle from glass, tiles, marble, granite, ceramic or other materials and only needs water for lubrication. Small incision resistance, chip easily, improved drilling speed, ease of decoration after opening. Surface by nickel plated for vitrified tiles, glass, tiles, artificial stone, ceramics and other brittle materials, drilling operations. Start your hole diagonally, make a round trace and then hold drill straight.