One of the coolest noisemakers ever made. The unit is basically a Boss DS-1 Distortion with a built-in tracking oscillator circuit that hold the last note you played before activating the feedback function (holding the pedal down). This lo-fi effect allows you to capture everything from droney feedback to synth-like string sounds. This infinite sustain, although basic, is very similar to what you'd get from using an Ebow or Sustainer System. The regular distortion circuit is a fairly smooth affair with a wide range of tonal possibilities that's quite capable of nailing most middle of the road overdrive and distortion flavors. The DF-2 went through a few subtle name changes over it's 10 year production run (Super Distortion & Feedbacker to Super Feedbacker & Distortion) Whatever the name, we think it's super for both distortion and feedback!