This unit is a MIDI controller, but it does not produce any sounds itself. You connect it to the computer or to a MIDI-capable sound generator. The Arturia KeyLab comes with software that can then take over the sound generation. For this, however, you need the computer.
If you want to know whether a device can produce sounds itself, it is best to look for an indication of how many there are.
Here, for example, there are 600.
Casio LK-280 (Grey)
However, you may be better served if you can get hold of such a device in a showroom.