Features Premium Material: These glass drill bit are made from premium boart material, which ensures hardness and durability. High Torsion: These glass drill bits provides high torsion to achieve excellent cutting strength and performance. High Efficiency: The drilling speed is fast, the hole is round and there is no breach, providing high efficiency. Wide Application: These glass drill bits can be used for glass, ceramic tile, stone, floor tile, marble and so on. Please Notice: Please keep adding water when the drill bits are working on the glass or ceramics, which can extend the service life. Specification: Item Type: Glass Drill Bit Material: Boart Opening Diameter: Approx. 12mm / 0.47in Handle Shape: Round Handle Application: Glass, Ceramic Tile, Stone, Floor Tile, Marble, Etc Package List: 10 x Glass Drill Bit Package List 10 x Glass Drill Bit