This is a great little oil diffuser. It's very simple to use and clean. Press the power button on the left one time to turn it on and it will run constantly. Press the power button a second time and the diffuser will cycle on and off every 30 seconds. A third press will turn the diffuser off.
Similarly, press the light button on the right one time and it will light up and cycle smoothly through different colors. If you press the light button a second time it will stay on whatever color it currently is on. Lastly, a third press of the light button will turn the light off. It also possible to turn on just the light and kind of use it as a soft lamp, if you don't want the diffuser itself to run.
When it runs out of water it shuts itself off. No need to worry about it overheating when it runs dry! I find that it is very quiet while it is running and it puts out a light cool mist.
All in all it's a great little diffuser and a nice addition to a spa bathroom or bedroom.