I’m selling my Famicom to NES adapter! I’m also including three Famicom games that I picked up on a trip to Japan. Super Mario 3, Donkey Kong 3 and Ultraman 2. They all function properly. The adapter was found in a copy of gyromite and I cut the cartridge in half and modified the adapter to fit cartridges. I took my time with the cutting and sanding, but it is by no means professionally done. You use it by orienting the Famicom cartridge backwards to the gyromite cartridge half, connect them together and then you use it like an NES cart. It works well in a top loader NES. I think it would difficult to remove from a normal NES since the gyromite half would stay in the system once the Famicom cartridge is pulled out, it should work but you’ll just have to fish the cartridge out.