Hi, I want to buy a used kiln from someone on facebook marketplace but both of us don't know a lot about them electrically. A plaque on the kiln has the specifications and next to volts it says '120/240/3w'. Does that mean it can work with both 120v and 240v? Also, it says that on a plaque but on the front it says 230v, which one is right? (The plaque also states the amps, watts, phase, serial and model number) Thank you!