ST600-PRO is a aroma machine designed for medium area of 400-600m3. The material is plastic and light. It adopt fluid dynamics & Venturi principle, to make the mist as small as micron particle, which makes scent to spread evenly and scent long-lasting in the space. The noise is only 25dba, so when it is working you can hardly feel its existence. The oil consumption of this model is low, but the scent performance is very good. It is very suitable for use in elevators, corridors, toilets and other places.