The the first and most popular Mission Pedal. The SP-1 is an expression pedal with a switch. The switch sits under the pedal and is operated by pushing down on the front with your foot in the same way as a traditional analog wah pedal. Typically this is used to turn a pedal driven effect such as a wah or vibrato on an off at the pedal itself. There are two 1/4” output jacks, one for the expression pedal and one for the switch. 

Don't forget cable to connect your expression pedal.Mission Engineering also make exceptional quality TRS cable to connect your SP-1.