This large-diameter nut is used to mount a M10-1.0 Bowden connector to the side of a storage box.
To use it:
Finger-tight is good. The fender nut can be tightened or loosened with a 32mm (1-1.4") wrench.
It really works nicely and saves having to locate/drill a bunch of little holes and find fasteners.
You can thread in a Bowden connector from the reverse side to hold it in place. Then use 4mm PTFE tubing to guide the filament.
The author marked this model as their own original creation.