Features: --100% brand new and high quality. --Can be used with a standard electric drill. --Always use lubrication (water), otherwise the diamond core drill will burn. --Materials and only needs water for lubrication. --This diamond coated core drill bit removes a complete circle from glass, marble, tiles,granite, ceramic or other. Specifications: Size: 6mm/0.23", 8mm/0.31", 10mm/0.39", 12mm/0.47", 15mm/0.59", 16mm/0.62", 18mm/0.7", 20mm/0.79,22mm/0.86",30mm/1.18" Material: steel Use note: Start your hole diagonally, make a round trace and then hold drill straight. Package includes: 1 set Diamond Hole saw(10pcs)