Descriptions: Our lapidary drill bits are made from diamond powder, precise and sturdy. It is perfect for drilling holes on the jewelry, ceramic, jade, agate, glass and amber etc. Using high-speed of drilling machine to drill will lead to a good drilling effect. Please use cold water to drill. Our drill bits are very sharp and you could use them for many times. It is a good drilling tool for you to choose from. Please Kindly Pay Attention: -Use cold water during the drilling hole operation -Use high-speed(Up 20000 RPM) to drill holes with our drill bits. -Be stable, don't shake Specifications: Condition: 100 Percent Brand New and High Quality Material: Diamond Powder Color: Silver Length: Approx. 36mm Diameter of Shank: 0.6mm Diameter of Head: 1mm Weight: Approx. 4g Quantity: 20PCS Package Included: 20 x Lapidary Drill Bits Please Note: 1. Please allow some errors due to manual measurement 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.