The Fender Mustang I & II amplifiers have four programmable knobs on the front panel. These are Gain, Volume, Treble & Bass. The Fender Mustang III, IV, and V have six programmable knobs. These are Gain, Volume, Treble, Mid, Bass, & Reverb. There is also a Master knob which is not programmable and remains "live" at all times. These knobs are part of each Preset. All knobs are normally inactive and will not show their actual setting when the Preset is selected. As soon as you turn any of these programmable knobs, they will become active.
When adjusting any of the Programmable knobs on the Mustang amps, you will see the Save light illuminate. If you change Presets without saving, you will lose the settings you just created. When using Fender FUSE with your Fender Mustang amp, FUSE will show the value of each programmable knob in each Preset in the Preset Editor.