The Wera Bit-Check 10 Impaktor 4, with Stainless Impaktor holder is designed for compact and organised tool storage. The set contains the premium TriTorsion system - bits and holder; designed for use in all heavy duty machines, but specifically Impact Drivers. Utilising a unique combination of anti cam-out technology, special material, hardening and precision manufacture, Impaktor bits absorb all of the damaging peak stresses associated with the impact power tools and dramatically extend service life. The Slim Stainless holder magnetises bits held within to provide screw-hold whilst allowing access into confined spaces. The Impaktor system is unrivalled in performance. Wera Bit-Checks feature a compact design to safely store bits and bit holders in a case that provides fast and easy tool selection. So slim it can fit into your pocket. Drive and size are colour coded for easy selection of the right bit. This 10 piece set includes the following:1 x 1/4in x 75mm Impaktor bit holder4 x Impaktor IMP 25mm Pozidriv bits: PZ2 (x3), PZ3.5 x Impaktor IMP 25mm Torx bits: TX20 (x2), TX25 (x2), TX30. Suitable for use with all machines.