Unlike most phase shifters, the Stereo Polyphase FEEDBACK control gives you the ability to vary the sound of the phase shifter, so that you have the final say on the character of the phase shifter’s tone. In ENV mode the Stereo Polyphase is a phase shifter controlled by an envelope follower. In LFO mode the Stereo Polyphase is a phase shifter controlled by a low-frequency oscillator. In EXP mode use an expression pedal (not included) to control the phase shifter. New in Box.