None of heaphone holders I found were not wide enough for my IKEA shelf and desk so I decided to create my own, hope you will enjoy it :).
Be careful when attaching the screw cap so you don't brake it (and reason I know that... :D).
20% cubic infill, 2-3 perimeters, 4 caused that thread in the holder was too tight so it depends on your tolerances but thread fits fine for me.
NO SUPPORTS NEEDED!
The author marked this model as their own original creation.