Connect this Fender 4-button footswitch to your Mustang amplifier (included with the Mustang IV & V, optional equipment for the Mustang III) to enable remote multi-function foot control. The footswitch display and LEDs show you some of the same information as the amplifier screen, so you can, for example, tune your guitar and select presets by watching the footswitch without ever looking at the screen onboard the Mustang!