Update 3/25/2020 Version 1.2 with rounder corners.

Bob from RetroRGB approached me about doing a custom back shell for his RetroUSB controller inside a cheap knockoff NES controller mod. I got going on the mod and decided that I would scrap the front shell from the cheapo controller and go completely 3D printed. Saving you from buying the additional parts for this mod. It turned out great and for me it was much more comfortable with the classic design.

Print wise I designed it for 0.2mm layers, 60% infill, and it requires no supports. Print both halves and use the original buttons, circuit board, battery, and screws from the RetroUSB controller.