The first Mission Pedal, the SP-1 is our unique switching expression pedal. There are two 1/4' output jacks, one for the expression pedal and one for the switch. The switch is operated by pushing down on the front with your foot in the same way as a traditional wah pedal. This is used to turn a pedal driven effect such as a wah or vibrato on an off at the pedal itself. The SP-1 is compatible with most MIDI controllers and processors with two or more pedal jacks. The SP1-R option adds a polarity reversal capability. This is a mini toggle switch that reverses the polarity of the potentiometer for compatibility with devices that require a reversed polarity.