With 1/4 "special bits (6,3 mm) in standard length (25 mm) and extralang for blind holes (80 mm), screwdrivers with positively locking the inserts by means of a spring - loaded sleeve(Male) and the counterpart with inner square and hexagon socket (female) Special insert for centric clamping of screw hooks and the like In a sturdy steel box (powder coated) Each part is clearly marked.