12 volts in mine. It uses one of those plugs like in the picture- I don't think it came with the plug- I think I salvaged one off an AC/DC converter for an old portable DVD player or something, or I may have bought a plug and hooked the wires up to it, I can't remember. It's powered off the post on the ammeter and grounded to the dash. I suspect it has a slight draw even when it's off, but that type of plug is easy to pull out and leave hanging for days I'm not driving, and put back in when I take the truck out. I guess I could wire it off the ignition switch to take care of the draw issue, but then I couldn't turn the radio on with the key off.
