The Foxpedal Quiver is a harmonic tremolo with some very cool features. There are controls for Level, Frequency, Symmetry, Rate, and Depth of the waveform. There are 5 different waveform shapes to choose from, and there is even control over the subdivision of the effect. It can also store up to 10 presets within the pedal, and up to 99 via the MIDI functionality. It has an on-board tap tempo switch as well as an input for an external expression or tap tempo device.