The SP1-LF was developed by Mission Engineering and FAMC Music, to provide the best possible expression pedal for the Liquid-Foot MIDI Controllers. Featuring an expression pedal and switch out similar to the SP-1, each pedal uses a custom wired momentary switch, and is factory calibrated and tested for optimal performance with your Liquid Foot controller right out of the box. The switch functions as an Instant Access (IA) button and can do anything a Liquid Foot IA button can do including turning effects on and off, and toggling between effects. The SP1-LF is compatible with all Liquid Foot MIDI controllers including the new LF+ Series.