Lunaroma's 500ml Ultrasonic Nebulizer is one of the best ways to enjoy the benefits of diffusing essential oils into the air. Using a water delivery method and ultrasonic technology, the essential oils never get heated. The 500ml nebulizer is their largest, making it the best choice for scenting larger spaces like living rooms, conference rooms and retail spaces. At the same time, it works well in smaller spaces when you use less essential oil. It runs for approximately 8-10 hours on continuous mode until the water runs out. You can also choose one, two or three hour diffusion time, which will turn off the system after the chosen amount of time. The diffuser has a light feature which either scrolls through a set number of calming colors, allows you to choose one color to stay on, or allows for no light at all. When on, it makes for great mood lighting day or night, or a soft night light as you drift off to sleep. This diffuser is easy to clean, and uses 10-20 drops of essential oil to scent approximately 900 square feet.