This Oberheim Xpander XP-1 is perfect functional condition and in excellent cosmetic condition, and appears to only have seen very light use over the years. It is the U.S.A.-made version. The original manual and a power cord are also included.
The Oberheim Xpander is a six-voice desktop version of the Matrix 12, with which it shares an identical voice architecture. In many ways, they are the most flexible non-modular analog synths ever built. Along with the Matrix 12, the Xpander was one of the last synthesizers designed and produced by Oberheim Electronics, and it represented the pinnacle of their voice architecture. Each voice has five LFOs, each with about five different wave shapes, plus the ability to sample most other modulators; five envelopes that can repeat themselves, sync to an LFO, and so on; a lag processor (like portamento, but more general); three tracking generators (that apply a series of linear functions to a value over its range); some ramp generators (the attack portion of an envelope); a 15-mode filter and a user interface to make all of this accessible. That all might sound complicated, but in the end, it's still just subtractive synthesis. If you can program a Juno or Jupiter, you can program an Xpander; things just have the potential to go much deeper.
The Xpander also has a useful CV/gate to MIDI conversion feature for communication with older synths. There are six CV and Gate inputs which use standard 1V/8va CV and positive gating. So you can connect up to 6 external sources delivering CV/Gate and convert that into MIDI. The Xpander's output options are also very flexible, with stereo and mono outputs as well as six additional individual audio outputs (1 for each voice). You can load a different patch on each voice, too, allowing you to use the Xpander as a stereo polyphonic 6-voice synth, as six individual monosynths, or any combination in between. Since you can stack six different patches, you can create some very thick, and very complex unison type sounds.