Building off the rich, warm, pulsating modulation of the Monument, the Monumental Harmonic Stereo Tremolo is an analog, optical tremolo bringing new controls, features, and width to the Walrus Audio line. New features available in the Monumental include the ability to save presets, blend between standard and harmonic tremolo modes, access to new wave shape and tap division options, and most importantly, a pan control to set the stereo spread of the tremolo to the right and left channels. This used unit is in great condition and comes in the original box. It has some velcro on the rear.