Descriptions: 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. Features: Diamond powder material:Made from diamond powder, high-quality, precise and durable to use. Excellent performance:The higher speed of drilling machine, the better effect of drilling bits. Drilling speed:The speed of drilling machine need to be reached 20000 RPM when you use our drill bits to drill holes. Durable:If you use the drill bit for many times, it will not be very sharp than the first time using.You could cut a little the top of it with plier, it will become sharp again. Application drill hole:Idea for drill holes on the jewelry, ceramic, jade, agate, glass, amber and semiconductor materials etc. 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% 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. Features Diamond powder material:Made from diamond powder, high-quality, precise and durable to use. Excellent performance:The higher speed of drilling machine, the better effect of drilling bits. Drilling speed:The speed of drilling machine need to be reached 20000 RPM when you use our drill bits to drill holes. Durable:If you use the drill bit for many times, it will not be very sharp than the first time using.You could cut a little the top of it with plier, it will become sharp again. Application drill hole:Idea for drill holes on the jewelry, ceramic, jade, agate, glass, amber and semiconductor materials etc.