The Husqvarna A600 HEPA Air Scrubber/Negative Air Machine is one of the most advanced portable air cleaners available. It is tested and certified for use as both an air cleaner and a negative air machine. Features 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 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. The A600 is a quiet-operating air scrubber with a sturdy, compact cabinet. Airflow can be set at two different speeds. The airflow is directed upwards to avoid disturbing dust on surfaces.