The Ultrasonic Humidifier has a built-in 7 color LED night light. The humidifier can run the whole night without needing to refill it. You can easily adjust the vapor flow with the control knob. Humidifier water tank capacity: 1-gallon aroma diffuser: Enjoy your favorite oil and water based aroma while humidifying the air. The aroma diffuser tray is compatible with essential oils, use your favorite oils such as lavender, eucalyptus, lemongrass, orange, peppermint, tea tree. The aroma will mix with the humidified air and release a scented vapor into the atmosphere. Give yourself a spa-like feeling in your home or office.