This is a wall mount for the LEGO Lamborghini Sián FKP 37 (model 42115). It is designed to easily attach your LEGO model to the wall. It looks great hanging on the wall, especially next to other LEGO models.
The mount is printed in white Prusament PETG, but any solid (not flexible) filament should work well. You simply need two of the blue LEGO Technic pins (you should have plenty of them as spares in the set) and a screw to attach it to your wall.