Wikipedia nes fourscore

The NES Four Score is an accessory for the Nintendo Entertainment System created by Nintendo. It allows four-player gameplay on games that supported it. The Four Score was released in 1990.

On the Four Score itself, there is an option to switch between two-player and four-player modes and turbo A and B buttons that give any of the connected controllers a turbo boost. The Four Score can also be used as a controller extension cable because the wire which leads from the accessory to the NES is several feet in length. The Four Score also came bundled with the NES Super Set.