This is the highly popular MKS-20 digital midi sound module of the 1980s used by Elton John and many other professional musicians. It is in very good condition and comes with operating manual, MIDI guidebook, power cable. Has 8 preset tone colours which cannot be rewritten and 56 which can be programmed to your taste. I am original owner - has had very little use-originally purchased for $2500 in late 80s.