The Music Keyboard was the final part of the Entertainment Computer System and was packaged purely as a keyboard and nothing else - you needed the computer adapter to be able to connect and play it. Once connected up however, you had in front of you a full size 49 key 6 note polyphonic keyboard (it says here) with the look and feel of a real organ keyboard. The TV display showed 2 bars and the notes you pressed on the keyboard so you could see as well as hear what you were doing. Extra carts were available to allow the keyboard to play different sounds and melodies, though I've never seen one in the wild......

You can see by the box that this keyboard was destined more to be compatible with the US Intellivision II rather than the UK's 'brown' standard Intellivision.....