Details:
"Has 2 humbucker pickups. Master volume, Guitar tone, balance, cut off , edit, LFO Mod, and mode 1,2,3 switch."
Note the auction is for the guitar unit only, not the synth.
EVERYTHING SYNTH
via HarriL in response to this post.
flickr by bandbajaobrothers.
Title link takes you to Elektrogemeinschaft, a German blog on avant-garde electronic music and instruments, Google translated here.
"It began on 3 September 1971. On this day that opened world-wide first specialist shop for Synthesizer, the Synthesizerstudio Bonn. In this illustration you see the shop in the Franzstrasse 29. The photo was made about 1977. For smoking one had to always rausgehen."