【Size】Diameter 3/8''-1''(10-25mm) ; Total length 65mm; Diamond height 50mm; Diamond Grit #50/60; 5/8''-11 Thread 【Application】Desinged to shape grind and enlarge existing holes in Tile Porcelain Ceramic Marble Granite Artificial Stone Quartz 【High Performance】High-quality Diamond Grain and Vacuum Brazed Technology provides much longer working life, high efficiency, durable and sturdy 【Cost-effective】Available in Two Diameters (3/8''(10mm) and 1''(25mm)) meet the processing needs of different apertures, don't need to buy several different core bits 【Attention】Diamond Finger Milling Bit can not be used to drill holes, but to shape, enlarge and grind existing holes. It fits on 5/8"-11 Thread Angle Grinder. Dry or Wet use. Very easy to operate. Recommended speed 6000RPM, maximum speed 11000RPM. If you want to use electric drill or other machine, you can use SDS or other Adapter