The 12 step (and I assume the soft step) works fine if you want to plug it into a laptop, which is easy enough at home or in some venues, but if you play pubs / clubs where you might not want to take a laptop, you probably just want to plug it into your keyboard or synth module. This is what this device does.
Its a little metal box, plug your 12 step in one plug, usb power into the other plug and connect the midi out to the midi in of your module / synth. Then press the pedals and make sound. There are no controls or settings in the module itself, it is effectively transparant in use.
The box is tiny and pretty robust (I have stepped on it). It comes with the (very long) leads you need to use it and the 12 step (unlike the 12 step) as well as a generic 5v USB power supply.
Not really much more you could add to this - if you have a 12 step, you pretty well need it, so it is good that it is so well made.