The Seymour Duncan Shape Shifter tremolo pedal features classic tremolo sounds yet allows control over every function for more wild tones, all in a true bypass and all-analog pedal. The first version comes in a gray enclosure with mono outputs, while the second version has a purple enclosure with stereo outputs. The Wave and Shape knobs provide access to customization of the waveform of the tremolo, with the Shape Shifter also featuring Depth and Speed knobs and a Tap Tempo footswitch. The Rate/Ratio knob changes the function of the Speed knob to either keep time with or multiply your tapped tempo, and the Channel Phase knob on the stereo version controls how out-of-phase the left and right channels are.