Keys has very close to full ratio keys to a standard piano. If you take it and put it up against a normal piano you'll see the keys span about the same length as two octaves, maybe by a difference of 2-3 mm.

This was a very critical aspect of the design and actually led to the implementation of the proximity sensors. We had to remove all controls to get this size but still be about the width of a 13" laptop - and the need for certain controls like octave transposition was the impetus for looking into other control methodologies like proximity based gestures.