LING'S SHOP 10Pcs Diamond Coated Core Hole Saw Drill Bit Set Tools For Tiles Marble Glass This diamond coated core drill bit removes a complete circle from glass, tiles, marble, granite, cer Materials and only needs water for lubrication Always use lubrication (water), otherwise the diamond core drill will burn Start your hole diagonally, make a round trace and then hold drill straight. Size: 6mm/0.23", 8mm/0.31", 10mm/0.39", 12mm/0.47", 14mm/0.55", 16mm/0.62", 18mm/0.7", 20mm/0.78", 2