The wera 8974 imp r impaktor holder with retaining ring and magnet impaktor holder to cushion extreme impulse peaks special torsion effect from the double torsion spring equipped with a ring magnet to easily hold longer and heavier screws also ideal for above head work particularly suitable for use with impact drivers the magnet can be retracted and in this way be disabled output suitable for bits with 14in hexagon head drive as per din 3126 c 63 and wera series 1design impaktor technology ensur