This is a set of two simple brackets that I designed because in the default configuration the Harley Benton Powerplant ISO-1 Pro didn't fit properly under the Spaceship 40 Pedalboard. The power jacks couldn't be accessed and the metal enclosure scratched the aluminum rails. Now the fit is much better and the PSU doesn't move, while the power jacks can easily be accessed.
Print two of them, I printed them in PLA with 20% infill but it shouldn't matter too much.