【Specifications】Diameter 3/8"(10mm); Total length 2-1/2"(65mm); Working length 1-9/16"(40mm); Diamond Grit #45/50; 5/8"-11 Thread 【Application】Desinged to enlarge, shape and grind existing holes in Tile Porcelain Ceramic Marble Granite Artificial Stone 【High Performance】High-quality Diamond Grain and Vacuum Brazed Technology provides much longer working life, high efficiency, durable and sturdy 【Unique Detail】The hollow design with 6 holes and the interior of the matrix is conducive to heat dissipation and chip removal 【Attention】Diamond Finger Milling Bit can NOT be used to directly drill holes. It fits on 5/8"-11 thread Angle Grinder. Dry or Wet use. Very easy to operate. Recommended speed 6000RPM, maximum speed 11000RPM