Uses ultrasonic technology to release fresh fragrance from the evaporation of water and essential oils. Ultrasonic technology uses no heat, maintaining the holistic and therapeutic properties of essential oils, and no filters to clean. Adjustable LED night light, gently fading between colours. Added safety feature of automatic shut down when water runs out. Tank capacity is 200ml max. 12W power output, Ultrasonic frequency is 2.4MHz.