I bought this pedal because I'm a lips head and it's made all the difference in my ability to play funky/psychedelic riffs. The left pedal is the harmonic mover and comes with three settings. The first two settings are easily the most widely accepted. The third is fairly intense compared to the first two settings. I've used it, but only on a lower volume as it can become overwhelming. The right side pedal is really a matter of how full and loud you'd like your harmonic sound. I prefer using the right pedal as a tool with dynamics and it's worked out pretty well so far. Overall, this pedal is a great collectors item, which makes it expensive.