I´m a big fan of Raspberry PI model 3 case for 40mm double V-slot rail with 40mm fan. I couldn´t attach it to my CR-10S Pro´s frame, so I made this design what I install on my printer cabinets wall.
Rail holes: 2x4,2mm
End of each rail other end is a 2mm end plate.
RealFilament PLA / PETG