Goes by several differnt brand names but is an "electrical management system" or "EMS". Monitors your power consumption and turns items on or off as needed. My 50 amp monitor shows which items it has selected to control at any given time. If I plug into 30 amps it so indicates just as it does if I switch to the generator. Smart gadget. If it hadn't been on my RV I probably wouldn't have got one. Now that I have used one I think they are the cats meow. Mine has a monitor panel that is approx 8 by 12 inches with lots of led lights.