A shelf holder to be fixed in accoustic panels (space between panels 13 mm). I wanted to use the space on top of my coat hangers.

The shelf on top should be 20 cm deep to fit tightly. I tested 4 holder with a 120 cm long shelf board holding ~8 kg easily. Since most of the panels are glued or stapled, I would be very carefull not to put to much weight on this and risking damaging the panels.

The small holder are first placed in between the panels and turned by 90° to grab inside the foam. Then the shelf holder can be fixed with a 3 mm screw (I used 1.2 cm in length). 

***EDIT***

New printprofile for different panels and shelfs. Be careffull to select the right one ;)

1. Added a second printprofile for boards of 15 cm deepth. Should fit on a A1 mini (total length 17,1 cm).
2. Added a version for accoustic panel with a space of 15 mm between the panels. It hast still a shelf depth of 20 cm.