This is the DUO-SFF (Super-Famicom+Famicom)
Set your Super-Famicom+Famicom side by side and safely power them both with 1 power supply.
Just set your 2 consoles side-by-side, plug it in and play. It's that easy. 
No step up or step down converter needed for any Retrogamecave power supply.
Retrogamecave power supplies are world-compatible.  International users need to provide their own cheap-plug-adapter (US to [your country] plug adapter)