This is a (Cakewalk by) Roland A300 Pro MIDI Keyboard Controller. This is identical to the Roland A300 Pro model that is still current, it was just from initial run prior to the Roland only rebrand.
These seem to be selling (NEW) for between £160-£200.
It's in mint condition, hardly used, though unfortunately I don't have the box or manual. It will be boxed and well packaged prior to delivery.
It's a premium quality controller (with plenty of knobs, faders and pads etc) and a real step up from cheaper models, both in build quality and feel.
For more info checkout the Roland A300 Pro page: