The Spa Mister Diffuser is a great addition to any space. It's beautiful, artistic, ultrasonic design fills your room with an ultrafine mist which will allow for our essential oils to be suspended in the air for longer periods of time and for better inhalation. This process does not heat essential oils, keeping their holistic properties intact. The Spa Mister uses tap water as well to keep things simple. The light can be set to bright, low, dim or off and this diffuser features 3 modes of running: continuous, 1 hour, and 2 hours.