The SNES Advantage is a large joystick produced by Asciiware, sold for the Super Nintendo Entertainment System. The device is meant to rest at a comfortable level on a flat surface—such as a tabletop or the floor—while the player sits behind it, but it can also used while resting on a players lap. The controller was designed to be used like an arcade game joystick and featured larger buttons action buttons than the standard SNES controller. It is used with both hands, one for the joystick and the other to manipulate the buttons.
The SNES Advantage was based heavily on the NES Advantage, with a similar set up, function, and features. The controller includes turbo options, a joystick, and support for 2 players, with an updated look to match the SNES console, sliders rather than knobs to control the turbo options, and individual turbo switches.
Source: Wikipedia, "Snes advantage", available under the CC-BY-SA License.