Specifications:Drilling Diameter: 20mm / 0.79"Drilling Depth: 58mm / 2.28"Shank Size: 9.5mm / 0.37"Overall Length: 84mm / 3.31"Drilling Method: Dry or Wet UseMaterial: Sintering Diamond (Cutter Head), Carbon Steel (Body)Shank Type: Non-slip Triangle ShankSurface Treatment: Electrostatic Powder CoatingRecommended Drilling Speed: 3000RPM - 6000RPMColor: BlackDescriptions:1. Suitable for drilling concrete, masonry, hard brick, marble, stone, and other hard materials.2. Can be dry or wet drilling. To prolong the using life, it is recommended to be used with water for cooling and lubrication.3. The large clearance hole facilitates the entrance of cooling water and the escape of chips and other particles from drilling.4. With sharp cutting edge, the core drill bits cut clean and fast holes, and make drilling process much easier.