These great sounding synths, regardless of version, don't show up all too often on ebay. This
particular example is the duophonic keyboard version:
Nyle Steiner told me a while ago that he sometimes made custom equipment with silver panels long after they had switched to the black painted ones.
The biggest reason they switched to black painted panels was that when making the silver panels, they were sanding the aluminum themselves. This
was a laborious task and it was difficult to get consistent results. The later brushed aluminum panels were made by using a wet wire brush and that
worked well enough. Nyle recalls there was also some discussion with his partners about using black because it seemed to be a popular color for synth
panels at the time.