This is a vintage Maxon FL-301 Flanger pedal from the 1980s. It is an analog bucket brigade flanger, built around the MN3207 BBD chip. It's great for those warm analog modulation tones with the perfect touch of bbd compression. Here's a rundown of the controls:

• SPEED: This controls the rate of the modulation. Turn it counter-clockwise for slower flanging. Turn it clockwise for rapid flanging.
  
• WIDTH: This adjusts the intensity of the modulation. Turn it counter-clockwise for subtle flanging. Turn it clockwise for deep modulation.
  
• REGEN: This controls the amount of output signal that is fed back into the input. Turn it full counter-clockwise to get analog chorus tones. Turn it clockwise to get jet-swoosh flange. At extreme settings, the pedal can get downright seasick.
  

The wave shape on this unit sounds kind of lopsided, and has a short cut-out point at the extreme ends of the wave sweep. It almost sounds like through-zero flanging, which isn’t possible. I don’t know if that’s how this flanger is supposed to sound, so I’m listing it in fair condition. Otherwise, it works fine and sounds really good

The pedal requires 18-volt dc power. You can power it with any standard 18-volt pedalboard power supply.