This compact diffuser is perfect for any small room. It provides an ultrasonic mist and makes no sound. Press #1 = Constant diffusion and color changing LED lights Press #2 = Set a specific color Press #3 = diffusion w/ no lights Press #4 = OFF This unit is very easy to fill with tap or purified water. A very affordable solution for any home. It auto shuts off when empty. Runs constantly for 3-4 hours.Ovvio International