Boss updates their phaser! This newer version adds a few new tricks like multi-stage phasing and some rise, fall, and step modes. 3 knobs take care of rate, depth, and resonance while the selector knob selects the various modes. The multi-stage portion of the pedal calls up different shades of the classic phasers of the past. Each stage has its own subtle differences and is quite capable of nailing warbly Korn-isms, Hendrix uni-vibey sounds, smooth sweeps of 70s pop, and even Quinn Martin-wacka-wacka funkyness. The remaining three modes offers some new interesting takes on the traditional phaser sound. The rise and fall speeds up or slows down the waveform as it approaches the top of the sweep making for some cool new psuedo-doppler-esque effects. The step mode is a sample and hold type deal that creates some neato trem-like stutterings. If you can shell out some extra coin, I highly recommend grabbing external tap-tempo switch (or expression pedal) so that you have complete control over the rate.