The PureGuardian® Deluxe Aromatherapy Essential Oil Diffuser with touch controls uses ultrasonic humidifier technology. Simply add just a few drops of our essential oil or your favorite and the ultrafine mist will quickly and continuously fill the room with the natural oil essence. The diffuser is quiet and won't disturb you when you're sleeping. The elegant, deluxe design has a clock display and includes an optional night light control and timer so you can set it to turn off once you've drifted to sleep. A gentle alarm will wake you and start your day with the oil essence. The 100ml water reservoir is BPA free and treated with Silver Clean Protection, which helps keep the tank cleaner longer.