A 600 is one of the most advanced portable air cleaners available on the market. It is tested and certified for use as both an air cleaner 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 at two different speeds. The airflow is directed upwards to avoid disturbing dust on surfaces.