Technical features: Uses: mainly used in coal mine anchor net support drilling hole protecting, provides the powerful guarantee for the tunnel quickly and efficiently. Features: the increase in hard rock (sandstone) drilling efficiency, blade wear, resistance is strong, without repeatedly grinding, long bit life. Not easy to shrinkage, hole rate is high, greatly reducing the roll, anchor waste, improve construction efficiency, reduces the labor intensity of workers, optimum lithologic widely. In the fractured rock, impact resistance and stronger,