One of the most advanced portable air scrubbers available on the market. It is tested and certified for use as both an air scrubber and a negative air machine. Thanks to a reliable filter system and a design that is perfectly matched to operation with HEPA class H13 filters, that are tested and certified at an efficiency rate of 99.99% at 0.3 microns, the air cleaner puts out superior air quality " be it when dealing with concrete dust, fine sanding dust or gypsum dust. It has two warning lights to indicate when the filters are clogged or leaking. A 600 is a quiet-operating air scrubber with a sturdy, compact cabinet. Airflow can be set to two different speeds. The airflow is directed upwards to avoid disturbing dust on surfaces. Performs 5 air changes per hour on 900 sq. ft. space 8' height