Quality Selection: These diamond drill bits are made of high 45 steel which is high quality durable. With a nickel-plated coated body to resist corrosion, which has a long service life. Large chip holes to ensure that when the punching smooth, punching accurate.Smoothly Cutting: A thicken diamond dust coating on the tops offers superior cutting strength for creates a high precision, smooth cut with no broken edges. Reduced drill speeds, low drill pressure, increased use of water lubrication will extend drill bit life considerably.Multiple Applications: The diamond drill bit can remove a complete 130mm diameter hole on glass, tiles, granite, ceramic. In addition to cutting holes for glass, the comes in hy for tile bottles, blocks jars, fiberglass, porcelain tile, ceramic, slate, marble, light stone. Not for use on Concrete or for depths beyond about 1/2inch.Specification:Finish: Nickel-platedColour:SilverMaterial:Diamondand45 steelSize:130mmPackage Contents:1 diamond drill bitHow to Use:1. Put glass drill into the driller.2. Because this cannot locate the center, so please cutting with it slowly with 45 degrees.3. Please cut a small mark first to locate the center, then you can cut the material vertically.4. The speed needs to be controlled, not too fast water is required during cutting.Attention1. When you using the diamond drill bits, please use lubrication (water). Otherwise, the diamond core drill will burn.2. Please do not cut metal material with this tool.3. Not for use on Concrete or for depths beyond about 1/2inch.4. Please keep the speed within 800-1000 per minute, low drill pressure, increased use of water lubrication will extend drill bit life.Only the above package content, other products are not included.Note: Light different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is and/- 1-3cm.