This is the expansion hub. It has ports to connect to the regular light hubs. In my application, I have 4 ports, and one light hub, at this point. But next month I am getting another light hub. So this made me need the expansion hub. Without it, I would have had to purchase another power cord. With this, you put the power in it. And when you run the cable from expansion hub, to the power in on the light hub, it powers the light hub. I installed a power switch to the expansion hub, so it will control all the light hubs, and other expansion hubs. So every light will come on at the same time. You can adjust that easy enough. Put the lights you want to control on the same light hub, and install a power switch on it. But of course the rest of the lights would have to be powered up first. But a great system. Easy connections, and real easy to setup.