Features: 1. Suitable for use in drill hole on glass, marble, tile or granite. 2. 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. 3. Can be used with a standard electric drill(Not Included). 4. Always use lubrication (water ), otherwise the diamond core drill will burn. 5. Start your hole diagonally, make a round trace and then hold drill straight.