Wera 840/1 Impaktor Bit Hex-plus SW4 x 25mm (Box 10)Wera Impaktor Hex Plus bits 25mm long with 1/4in hexagon drive , suitable for DIN 3126-F 6.3, ISO 1173 bit holders.The Impaktor technology ensures 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.