Gearank

This USB powered controller keyboard is very highly rated by owners - partly due to the fact that it is targeted at iPad users even though it will work with any computer or tablet that has a USB port.

It has full size keys (in terms of width) which are velocity and pressure sensitive with polyphonic aftertouch.

The CME Xkey 25 comes bundled with a free app for iOS, Mac OSX, and Windows.

It has one of the slimmest profiles of all the 25 key controllers available.