This diamond core bit removes a complete circle from glass, tiles, marble, granite, ceramic, or other materials and only needs water for lubrication. Excellent for making clean and precise holes on glass and tiles. Diameter range: 6/8/10/12/14/16/18/20/22/25/26/28/30/40/50 mm. Can be used with a standard electric drill. Note: Always use lubrication (water), otherwise the diamond core drill will burn.