The TBD Oscillating Fuzz / Feedback Loop consists of two effects in one pedal. First, there is the feedback loop (with photo-sensitive eye), which enhances effects placed in the SEND and RETURN loop of the TBD. Second, there is the oscillating fuzz, which adds an amazing amount of texture (and if needed, chaos) to the effect in the feedback loop. The feedback loop runs before the oscillating fuzz, and they are both seperate, which means you can have one on at a time, or both.