This is the SOLOIST headphone amplifier, perfect for enjoying music at home. I purchased it in the US around 1985 when I lived there. It's a headphone amplifier that condenses the Rockman sound created by Tom Scholz into a lightweight, compact body. It has three sound settings: "DISTORTION" for high-power sound, "EDGE" for a light crunch suitable for rhythm playing, and "CLEAN" for clean sounds. Effects include CHORUS/STEREO/MONO. It can be powered by the dedicated AC adapter or 8 AA batteries. AUX input allows for mixing, and it can also be connected to a mixer or guitar amp. I hadn't used it for many years, so there was some crackling when moving the slide switches, but I've confirmed it's working, and the condition isn't bad. The dedicated adapter is included. The box is not included. The Rockman Soloist, produced by Scholz Research & Development (SR&D) in the 1980s, is a vintage, pocket-sized headphone amplifier designed by Tom Scholz of the band Boston.