Living Libations Ultrasonic Aromatherapy Diffuser has a two-hour cycle where the diffuser nebulizes oils for three minutes and idles for five minutes. This on-off cycling produces a steady state of aroma in the room. After 2 hours, the diffuser shuts off automatically. It will also shut off if it runs out of oil. The diffuser has a colored light sequence, and there is a nob to adjust the amount of aroma produced. The cord is AC100-240V and USB.