Electro Harmonix Tube Zipper Envelope Follower Distortion Pedal Unzip your soul. Just picture your guitar signal being massaged by a complex set of filters moving through a vacuum tube maze. Energized by two 12AX7EH tubes, the Tube Zipper's patented moving filter gang tastefully adds controlled analog harmonics to your signal. In typical EH fashion, each control can be set over the edge, generating a host of novel tones. Add some Tron or Trill a la mode! 12AC-1000 power supply included.