These dimmers have the same features as the IML DC Electronic Dimmers but with an ability to operate on either 12/24VAC (from transformer) or 12/24VDC (from battery). In a straight Low Voltage AC system, simply wire this dimmer on the low voltage output side of your transformer to control your light fixtures. As an additional feature, when wired with a 12VAC or 24VAC relay, your Low Voltage AC dimmer will automatically switch over to a DC back-up if your AC power is shut down or lost. (No need to wire a separate DC grid). Not recommended for use with any type of LEDs. This dimmer is compatible with Imtra's magnetic toroidal transformers and will not work with our electronic transformers. Not recommended for use with LEDs as it will cause premature LED diode failure.