via this auction, also on Reverb
"1981 Roland Studio System-100M Modular Synthesizer and Model 181 keyboard controller in exceptional condition and in perfect working order. Stunningly well-kept and complete with numerous patch cables as well as the original shipping box for the keyboard controller, this vintage analog synth is complete and freshly serviced.First released in 1978, the System 100M was Roland’s scaled-down follow-up to the iconic System 700, their first truly modular unit. It was released in tandem with 13 individual rack modules available for integration into the system. This particular System 100M features the 191-J 5-module case rack. While the 181 keyboard and 191-J case are not not from the same original unit, they were (according to serial numbers) produced in short proximity to each other.
There are 5 individual modules currently mounted in the 191-J case:













































