Express yourself. Like never before. The Electro Harmonix Cntl Knob Static Expression Pedal gives you versatile control of any device with expression control jacks. This is everything you want from an expression pedal at a fraction of the size. Powerful effects. All at the touch of a button. The Cntl Knob lets you set two preset values representing two positions of a traditional expression pedal. With one click you can toggle between them giving you access to a wealth of vastly different sounds. & with a TRS+/- switch on board the Cntl Knob proves highly flexible. This is everything you need to upgrade your rig.