With its smooth outside, you can not clamp a lampshade firmly on the lamp socket (for example, a socket with external thread and threaded ring would be necessary). With a beautiful light source (e.g., the Edison Lamp mit sichtbaren Leuchtfäden) and a textile cable, the socket does not need a retro design cover in order to look good. On the rocker switch, you can switch the light on and off independently of the wall switch directly on the socket.
The strain relief, made of metal, has a small screw on the side, with which you fix the lamp cable after pulling through so that the screwed contacts of the connecting wires are released. You can also simply unscrew the strain relief if you want to attach your light to the ceiling with a stiff threaded tube through which you pull the cable. Important: Since the openly accessible strain relief (and the threaded pipe) can conduct electricity from metal, you must also connect the 3-wire cable to the protective conductor (yellow-green grounding).
Small Tip:If you have screwed together this version already once prematurely, you can open it again with a trick: namely, a small plastic corner on the inner core pushes when screwing against the outer wall and locks the screw mechanism. If you push them carefully with a current tester inwards, the lock will release, and you can unscrew the socket again.