Casio CTK-481 keyboard musical information system, fully tested with adapter and works perfectly. 

medium-sized keyboard with 61 keys

Cosmetically this keyboard is in great shape with Basic specs:

100 tones//12-note polyphony (max.)//5-channel multi-timbre MIDI/

GM simulation mode (GM tone map)

Auto-accompaniments (controllers: synchro/fill-in, start/stop)100 rhythms