Long 3/8 "Hand and machine socket screwdriver insert (ISO 2725 part 3) with ball locking groove; for hexagon screws and nuts. For hand or machine screwing (not type) even with deep-seated screws and projecting threaded rods. With tool selector Take it easy with color coding according to size - for easy and quick selection of the right tool. Good grip that is easy to get hold of, even with oily hands. The hexagonal profile enables the transfer of large forces and loads the edges of the nuts and screw heads less than a twelve-sided profile does. in addition, the triangular profile is superfluous, even in confined spaces, thanks to the minimal return angle.