This is a headphone rest for storing my Sony Noice Canceling headphones when they are not in use. The headphone rest mounts on the Ikea "Bekant screen for desk" (https://www.ikea.com/us/en/p/bekant-screen-for-desk-gray-70268811/).
The headphone rest is nicely rounded to avoid unwanted bumps in the padding of the headphones.
The headphone rest is printed in two part for maximum strength. This also makes it easy to design a different hook for mounting on other furniture or directly to a wall or something. The two pieces snaps together. The STL files has a gap of 0.2 mm, which is OK when printing on my Ender 5. The FreeCAD file is included, to allow easy adjustments of gap size or design alternative hook part.
I am a FreeCAD novice, thus the structure in the FreeCAD is probably sub-optimal - I am still learning.