15 sizes diamond drill bit set Diamond drill bit size, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 35mm, 40mm, 50mm. Meet most of your different Needs. STAINLESS, FAST FAST Made of high strength carbon steel with smooth nickel plating surface, glass drill bits put lower resistance to the minimum, makes it easy to drill precise holes in seconds. SHARP & SMOOTH CUT Coated with high quality diamond, the diamond hole saw produces a precise, smooth cut without broken edges. SPEED KILLS Reduced drilling speeds, low drilling pressure and increased use of water lubrication extend the life of the drill considerably APPLICATION Drill Glass, Tile Bottles, Blocks Glasses, Fiberglass Porcelain Tiles Ceramic, Slate Mable, Granite Light Stone. Excellent for making clean and accurate holes on glass and tiles. Not for use on concrete or for depths over 1/2 "". Material: steel Color: silver 15 Size (outer diameter): 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 35mm, 40mm, 50mm Package: 15 * Diamond Coated Drills use note: 1.Start your hole diagonally, make a round trace, then keep the drill straight. 2. Always use lubrication (water), otherwise the diamond core drill will burn. 3. The low drilling pressure and the increased use of water lubrication extend the life of the drill considerably. 4.Not for use on concrete or for depths over about 1/2