Permanent True HEPA air filter with germ reduction. Ideal for large rooms. The True HEPA filter removes 99.97% of common household particles as small as 0.3 microns from the air passing through it such as dust， pollen， tobacco smoke， and cat dander. Reduces airborne germs such as bacteria， virus， and fungus. Activated carbon pre-filter reduces unpleasant odors. The glass-fiber HEPA material helps remove airborne particles without the use of chemicals or other treatments. Circulates room air up to 5 times per hour. Also features electronic filter indicator which reminds you when to replace filters. 3 air cleaning levels plus Turbo Clean setting. Easy tap electronic controls with a 2， 4， and 8 hour timer. SurroundSeal technology helps minimize air leaks and insures that the air passes through the filter， capturing particles. AHAM certified. AHAM CADR (smoke): 300. Requires both the filter and carbon pre-filter to operate. Filters included.