Walrus Audio Monumental Stereo Harmonic Tap Tremolo Effect Pedal w/Box - UsedAn analog, optical tremolo that can give you traditional, black panel style tremolo, or turn the "S B H" knob to blend in harmonic tremolo, until it becomes fully harmonic. Tap tempo and ramp speed are controlled by the second footswitch. Rate, depth, and subdivision knobs give you full control of how the effect sounds. There is a small blemish on the front of the pedal.