The wera 8684 imp dc impaktor square plus 50mm bits ensure an above average service life even under extreme conditions thanks to a best possible utilisation of the material properties and optimally designed geometry particularly suitable for use with conventional impact drivers the rough diamond coating reduces the danger of any slipping out of the screw head due to the enhanced frictional resistance for best results use with the impaktor tri torsion bit holder suitable for din 3126 d 63 iso 117