They are flexible shaft drill bits designed for drilling inside walls, or around corners. Fish eye holes are provided at each end of the bit, which allows the operator to pull wires from either direction after drilling. An insulated steering guide helps the operator to manipulate the bits within the wall cavity. All Piranhabits are mig-welded to a flexible chrome silicon shaft for superior strength. These invaluable tools can be inserted through small wall openings by the operator to bore holes through studs within the wall cavities without damaging finished walls or ceilings. Carbide/Masonry Piranhabits are for concrete or stone.