All Malibu transformers I've seen have been 12volt AC. Depending upon the LED modules, they could be designed to run either AC or DC. I've been starting to run more and more of my yard off a Malibu transformer. What's nice is I can setup my yard, then take several hundred feet of Malibu wire and lay it out around the yard. Then I setup my props with the quick pinch connectors and its an easy hookup. My LED spot lights are designed to run either AC or DC so that works fine. On other items like wiper and vent motors or standard LEDs, I solder together simple bridge rectifiers at each prop to convert the Malibu AC to DC and all is good.