Trister's Ultrasonic Aroma Diffuser is both a diffuser and humidifier. It gently vaporizes essential oils to give a fresh fragrance in your home. It also humidifies the air to help you sleep better, cough less, and alleviate dry sinuses. , Contents: , Trister Ultrasonic Essential Oil, Aroma Diffuser Unit, Power Adaptor, Measuring Cup & User Manual