This is a Boss BF-2 analog flanger, purchased approximately 45 years ago. It's an early production model, notable for its silver screws. I recall that Japanese-made flangers of the time typically had three knobs, but this model introduced the Manual knob, significantly expanding the range of sound creation. It can produce the so-called "jet mode" sound, but setting Manual and Depth low and Rate high creates a strong chorus effect. Apparently, artists like Gary Moore used a setting with Manual high and a touch of Resonance to achieve a unique phasing sound. The condition is as it was when purchased, but the adapter plug is loose and has been reinforced with paper. Please see the photos. It's old, so there's some minor soiling, but the unique sound is surprisingly fresh. The unit only, no accessories included. Thank you.