thats german, its optional equpment on those queer sprinter vans i am cursed to work on. ben has some info for you. it really works well, and its nice because its like an alarm clock you can set to warm your truck up. it should be capable of bringing your engine up to 180* within 10 minutes. it also assists in engine warmup after you have started the engine cold. im not sure if yours is "programmed" to do it, but it will also kick one periodically while you are driving to keep the engine at an acceptable running temp.
that pic is just of the controller. there should be a shoebox size piece somewhere with coolant lines running to it. that is the actual heater. its just like one of those kerosene space heaters, that gets coolant pumped through it.