Dual-drive spline impact bit set with adaptor and locking coupler offering the option of 1/2" and 3/8” drives. The bits also have a 17mm Hex (6pt) head so that a spanner or ratchet wrench can be used when space is restricted. The set includes a useful range of sizes from M6 to M18 and are manufactured from one-piece chrome molybdenum, hardened and tempered to withstand the demands of impact tool use. A professional set presented in an EVA foam storage tray, for convenient tool drawer storage.