That looks like nothing, but that is the back of my auxiliary modules for the 2600 #semimodular #synth. I needed all the 2hp space of this 19" #eurorack rails, so I put the power supply in the back. The rails are slotted for square nuts only on the front, so I tapped some 3mm threads in the back so I could mount some standoffs, and mount the eurorack power supply to them.