For those electronic keyboards with an input jack labeled ""SUSTAIN,"" the FC4 model is used in the same manner the sustain pedal on an acoustic piano is used. After pressing down a key, the note will continue to sound utilizing the technology of the FC5 until the sustain pedal is released. The FC5 can also be utilized as an FS controller in synthesizers, tone modules and drum machines.A compact version of the FC4, the FC5 performs similar to an acoustic piano's sustain pedal providing expression and feeling to any performance. The FC5 can also be used as a hands-free on/off switch for activating effects or even recording.