This is a flag hanger to be attached to the shelf system "RS" by the German manufacturer rs Möbel/möbelum.
It has two 8.5mm holes for mini flag poles with 8mm diameter, one vertical and one angled 30 degrees.
On the bottom, there is a hole to attach it to the RS shelf with the metal mounts for the shelf boards.
There's guides on the side to prevent it from tilting.
The author marked this model as their own original creation.