A very, very useful tool for your Fender Mustang amp. Highly flexible, can be programmed to control several different functions. Plug it in, and choose from your amp's control panel what you want the pedal to do, and just use it. Very easy to understand.
The pedal can also be used as a tuner, just press and hold one of the buttons, and you're in tuner-mode.
Comes included with the Mustang 4 v2 and Mustang 5 v2, but can be added to the Mustang 3 v2 as well, together with the two button footswitch that comes included with that amp. Durable, sturdy, well-made, and functional. What more do you want?