This is a very rare vintage 1977 Mu-Tron Flanger. This pedal flanger, serial number 1111, is the rarest of Musitronics effects. It’s extremely clean, though it is missing a screw on the bottom plate. It works perfectly and sounds amazing. It was recently serviced, and though it worked fine prior, with the replacement of several capacitors, this effect now works and sounds like it did when new.