It uses electrical oscillation at ultrasonic frequencies. The ceramic disk changes the electrical oscillation into mechanical oscillation, creating the mist and water spray. The single unit mist maker diffuses approx 100 ml of water per hour. Its simple to set up, just drop it in water between 1.5-2.5 inches deep, plug it in, and instant fog! For large fountains or outdoor ponds, check out our 3 and 5 and 9 disk units with exterior transformers and 25 feet of cable!