Yakamoz Diamond Drill Bit Set Hole, 10PCS Hole Saw Diamond Drill Bits for for Glass, Ceramics, Porcelain, Ceramic Tile, Marble, 4-12mm Feature: Various Sizes - 5 Sizes of total 10pcs diamond hole saw bits - 4mm, 6mm, 8mm, 10mm, 12mm Ideal Application - Perfect for drill glass, tile bottles,blocks jars, fiberglass porcelain tile ceramic, slate Mable, granite light stone Super Material - These diamond drill bits made of high-speed steel that is durable and have a long sevice life,which are high quality and good performance that excellent for making clean and accurate hole. Sharp and Smooth Cut - Coated with high quality diamond, the diamond hole saw creates a high precision, smooth cut with no broken edges. Reminder - Reduced drill speeds, low drill pressure and increased use of water lubrication will extend drill bit life considerably. How to drill correctly: 1.Firstly, mark the point where you want to drill the hole; 2.Next, fix the drill at the angle of 45°to make a drilling trace at a high rotating speed;and add water during the drilling process; 3.Then drill vertically from the other side of the drilling trace at a slow speed to prevent breakthrough. ▶Please Note▶ When you using the diamond drill bits, please use lubrication (water),otherwise the diamond core drill will burn. Not for use on concrete or for depths over 1/2". Specifications: Material: High quality carbon steel, Uniform diamond coating. Cutting Diameter: 5/32-inch (4mm), 1/4-inch (6mm), 5/16-inch (8mm), 3/8-inch (10mm) and 1/2-inch (12mm) Cutting Depth: 1/2-inch (12.7 mm) Package Includes: 2 Set of 5Pcs Diamond Drill Bits - 4mm, 6mm, 8mm, 10mm, 12mm (Total 10 Pieces)