Sorry I wasn't too descriptive, I was out waiting outside a shop and my wife came back out!
As dad says, this is per key. It is very handy. i don't really play individual keys, I use it for chords such as backing chords - it also has a hold, so you press a key, it plays a chord and holds it until you press another one or the cancel button. Very handy for backing pads / strings etc. Really fills everything out nicely but doesn't involve too much tap dancing.
Very useful device.
Although I have a Yamaha keyboard for piano playing for a couple of tracks now:
PS - that was the first outing, the keyboard is on a holder now so needs less duck tape!