Ultrasonic diffusion, has 2 modes, continuous or intermittent (30 minutes on and 30 minutes off...). You can program operation for 1 h, 2 h, 3 h, 7 h or until the tank is empty.
Independent ambient light selection of diffusion in various modes - Intense, gentle, Zen respi (progressive). or sleep, stays on for 30 minutes and turns off.