The SNES Super Advantage is an arcade stick similar to the NES Advantage. It was made by Asciiware. It was made to simulate an arcade joystick.
One difference between the NES Advantage and the SNES Advantage is that the Super Advantage is a third party controller, made by Asciiware, and the NES Advantage is first party, made by Nintendo. The Super Advantage also has it's own "NES Max", called the Asciipad, or the Super Nintendo Turbo Controller.
The Super Advantage has a slow button, an eight direction joystick, the turbo sliders, and speed sliders. Unlike the NES Advantage, the Super Advantage uses sliders instead of knobs, and also has new speed sliders, to speed up the turbo sliders.