This 24VAC/500mA transformer powers both your OpenSprinkler AC controller and your sprinkler valve. Please note that this plug is only for 110~120v U.S. outlets. Due to the low current rating (500mA), it is NOT suitable to run more than 2 valves at the same time (i.e. simultaneous zones). If you need to run more zones at the same time, please find a 24VAC transformer with larger current rating.