This is what is says on retrousb.com
:START:System Compatibility List:
Works on authentic Nintendo Systems including NTSC, PAL A, PAL B, and Asian top loader and toaster systems.
Works on Famicom using 72-60 pin converter.
Does NOT work on clone systems like the NEX, Yobo, or FC Twin.
Untested on portable systems, not likely to work.:END:
The compatibitly list states that it works in a US NES, a European NES as well as a Famicom. The list also states which clones which it's doesn't work on and that's no surprise because these clones listed above, the Retro Duo makes them obsolite because it plays more original software.