Features:*Lapidary drill bits made from diamond powder, high-quality, precise and to use.*Idea for drill holes on the jewelry, ceramic, jade, agate, glass, amber and semiconductor materials etc.*The higher speed of drilling machine, the better effect of drilling bits.*The speed of drilling machine need to be reached 2000 RPM when you use our drill bits to drill holes.Please use cold water during the drilling hole operation*If you use the drill bit for many times, it will not be very than the first time using.You could cut a little the top of it with plier, it will become again.Please Kindly Pay Attention:1. Use cold water during the drilling hole operation2. Use high-speed(Up 20000 RPM) to drill holes with our drill bits.3. Be stable, don't shakeSpecifications:*Material: Diamond*Color: Silver*Length: Approx. 36mm*Diameter of Shank: 0.6mm*Diameter of Head: 1mm*Applications: jade, agate, stone, crystal, jewelry, ceramic, glass, semiconductor material drilling*Place of Application: Drill Bit, Small Bench Drill, MillsQuantity: 20PCSPackage Included:20 x Lapidary Drill BitsNote:1. Please allow some errors due to manual measurement2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real as standard.