The Gurgle and Moan is an envelope filter effect. This is a prototype pedal, and it does have some quirks and rough edges. On a few of them that we have built they oscillate with the resonance knob cranked. Also there is a bit of a "gurgle" in the background due to some crosstalk issues with the control voltage circuitry. I thought it sounded cool, although it may not be what everyone wants in a filter. This is a prototype pedal, and has no artwork, or labeling on the face of the pedal. There is a sticker on the back with a brief explanation of what the knobs do. Controls Lower right knob: Shape - Varies the shape of the filter from band pass or low pass. Lower left knob: Resonance - Accents the cut off frequency of the filter. (At max setting it may oscillate) Upper right knob: Depth- Varies how far your playing dynamics will modulate the filter cutoff frequency. Upper left knob: Frequency - Varies the cut off frequency of the filter Warranty: If it ever breaks send it back to us and we will fix it, unfortunately we no longer cover polar bear attacks, alien abduction, willfully destroyed pedals, or any claims involving time travel or toaster repair. This pedal can be powered by a 9V battery or a standard boss style barrel plug adaptor. Has an LED, True bypass, and a powder coated finish for durability.