I tried to find a simple yet efficient 3D model for a hook to hang my backpack under my desk. I designed this hook and thought it could be used by someone else.

You will need two screws to fix it under your desk, I used 4mm wood screws (the length depends on your desk, mine were 20mm long.)

I added holes so your screwdriver can go through.

Tested with a 8kg bag, didn't break!