Super Game Boy Commander controller for Super Famicom. This may be one of the least necessary controllers I’ve seen, useful mostly for people who weren’t able to adjust to playing Game Boy games with two buttons that didn’t have a speaker vent under them.
Maybe we didn’t need it over here because our SNES controller buttons were already a shade of purple, so it was less jarring of a transition from Game Boy to SNES. Okay, to be serious, when in Super Game Boy mode, the unused SFC buttons are remapped to other functions like slowdown.
It may not be necessary, but it’s kind of awesome. It’s NCSX’s sale item of the week, for $19.90.