Imagine yourself with a microphone in your hand, walking on the stage towards the lectern. Where will you put the microphone? Well, this microphone holder is your solution: it will keep your microphone close to your mouth, whatever height this needs to be, freeing your hands. The clamp accepts microphones of various sizes (wired or wireless microphone).
The microphone wiring, if any, goes down beside the lectern, not through it. The holder and its arm are installed on a small plate that you screw (2 screws) to the lectern's top.