Bi torsion extra hard bits are harder wearing than standard bits and are ideal for screws driven into general construction materials soft jointing hard reliable bit which ensures significantly extended service life over standard bits when used with a bi torsion rapidaptor the two unique torsion zones one in the bit and one in the holder work together to absorb peak loads placed on the bit significantly extending bit service life standard 14in hexagon drive this bit box contains 20 x pz2 14in