Stone and concrete drill Design: With round shank. The computer calculated twist profile ensures optimum removal of drilling dust, smoother drilling and optimum impact energy transport. Extremely long tool lives are achieved by the high strength soldering of carbide plates and the annealed surface, which results in a guaranteed higher break-resistance in impacts and higher strength for armouring hits. Up to 50% more holes than standard concrete drills. Certified by the Prüfgemeinschaft Mauerbohrer. Application: For concrete, stone, brickwork, brick, light construction materials, granite and marble.