JINGLING 1.6 mm Diamond coated Lapidary Drill Hole Needle Solid Bits for Jewelry Agate Pack of 10Pcs Product Name: Lapidary Diamond Drill Bits, Diamond Drill Bits for Stone Jewelry, Gemstone Drill Bits Head Diameter: 1.6mm; Total length:53mm; Shank diameter:0.9mm; Quantity:10Pcs Application: Suitable for use in drill hole on the jewelry, gemstone, jade, agate, amber, beeswax, crystal Suitable Machine: high speed bench drill, bench drill, fixed drilling machine, etc. Use with water as a lubricant; Max speed: 18000 RPM