Series 300 screwdriver, actually a hexagon nut driver for regular hex bolts and nuts. With multi-component Kraftform handle. A nut can be installed much further on the threads than with a regular socket nut, the piece of protruding threaded rod will simply fit into the hollow shaft of the nut driver. Shaft: Round throughout, hollow inner. Nut size: 5mm. Shaft length: 90mm. Handle length: 98mm. Shaft diameter: 7.2mm.