“Sounds great and very flexible. The knob controls are: Feedback, Rate, Width, Tune, Mode. Mode has four options — Filter Matrix, Flange, Chorus, and Slap Back. The I/O Options are Input, Direct Out and Effect Out. There is also a Blend On switch which provides for an interesting effect on the sound.”
Information on how this effect was used by Nirvana’s Kurt Kobain can be found here.
More information here: