I purchased this URPOWER Essential Oil Diffuser along with another of the same brand, but a smaller size and capacity. This diffuser will take up to 300 milliliters of essential oil and water mix. The unit has 4 settings for operation. 60 minutes,180 minutes, 360 minutes and ON. So, you can set the unit to work whichever amount of time best suits your needs, or if you prefer, you can set it to ON and it will run until there is no more solution left, When it will turn off automatically. The unit also uses four bright LED's that give the whole case a soft glow in various colors. There are two separate control buttons. One controls the time and the other controls the light. By default the diffuser will start at 60 minutes and cycle through all the LED colors. I have discovered that some colors seem to work better with different essential oils or moods. When the color cycles around to what you want, push the "Light" button again, and it will remain that color of light. The diffuser is very quiet while it is running. All you hear is a soft hum, and occasionally it will gurgle just a little. (I don't know why) Which essential oils you use and whether you blend them or not is up to you. Each oil generates its own feelings in you according that oils properties. Here are a few things I have discovered that might help you enjoy your diffuser. The oil and water mixture seems to be most effective (and you can smell it better) if the mix is fresh. I have tried making up twice as much as I needed, thinking that I could simply turn it on the next time I wanted to diffuse some oil. This doesn't work very well. The oil I was using was Lavender. It is very strong and easily smelled. When the mixture had sat for a day inside the diffuser it was not as strong smelling and actually smelled a bit acrid. Mix up what you think you will use in one go, you will be pleased with the results. The essential oils, two things, buy pure, medical grade, organic, concentrated oils. Anything that contains chemicals used to extract the plants natural oils; definitely disappointing, as you will smell the chemical and the desired effects of using that oil are diminished. Secondly, be sure to clean the unit between uses with clean water and liquid dish soap. The oil WILL stick to the inside edges and the bottom of the tank. Pretty soon your oils start to mix and again, the experience is less satisfying. I like to dilute DAWN dish soap in a spray bottle, keep it under the sink, spray a few good sprays into the tank, rub around with a cloth or sponge, rinse, drain and dry. Be sure to pay attention to the "Drain Side" with the arrow pointing to the top. Pour the water out of that side! If you pour the water out the other side it may enter the "Air Outlet," go into the motor and that's it, ruins the unit. I learned that the hard way! You can also run clear water through the unit as a way to clean out the area where the water is atomized if you want to. URPOWER recommends that you do this BEFORE the first use anyway. This diffuser comes with a great little plastic mixing cup with markings from 20 ml. to 150 ml. Works great for mixing up the exactamount of oil/water blend that you need. The AC adapter plugs into the bottom of the unit. When you are placing the "cap" over the tank and diffuser, match the URPOWER logo and the times up. Let the "cap" fall naturally to the bottom unit and turn slightly clockwise. When you hear the click, it's firmly in place. If the "cap" isn't on tight the unit won't work, so if the plug and everything seems ok, try re-attaching the "cap." That's it! I have gotten many months now of flawless use from this diffuser. Amazon chose it as "the best" in its own tests. That's why I purchased it. Now after using it I can definitely recommed this diffuser! Thanks for reading my review. Good Luck and have fun!