KORG ES-50 Model 0

via this auction
"This keyboard is identified as "Model 0", but I believe it is the ES-50. Strings that sound like strings are produced by the three oscillators and separate double envelope generators per note. Its built-in Chorus Ensemble Effect creates a dramatic stereophonic panorama of sound and ca project a true rotating-speaker sound. The Tremelo and Key Click features deliver a genuine vibes piano sound. And real-sounding acoustic, clavi, and celeste piano effects are also at your fingertips. [It] combines the equivalent of two completely different instruments (Strings and Percussion), creating a total of nine different voices... Serial No. is 231037"