Casiotone 610 Synthesizer, best known for the great organ sounds it can produce, the real stereo chorus widens the sound up nicely, sounds huge through a large reverb. The electric piano sounds are nice as well. 

Very heavy and sturdy build quality. On board drum accompany can be fun too. 

The built-in speakers do get quite loud, suitable for smaller performances and jams, when this originally came out, it was marketed as a performance and "professional" bit of kit. 

Has 61 full size keys. Condition is that everything functions, for something this old, it does have a few scuffs here and there, but nothing that affects the functions.