This controller has been designed specifically for use with our large power pack (FL-1391) for our low voltage connectable lights range & powers up to 600 LEDs. The large power pack comes with 4 ports that can run separate light strings at the same time, & is only supplied with a function controller for one port, so you'll need this controller for each port you need to use. Note: only 600 LEDs can be run from a single port at any one time. So if your display contains more than 600, then simply use the other ports to continue your display.