Holmes HAP9422-UA HEPA-type Tower Air Purifier operates quietly to help remove up to 99% of airborne particle such as pollen, dust, mold, pet dander and smoke, providing relief from odor and irritants in the air. Maximum dust removal traps and locks 30% more dust and particles. HEPA type filter captures particles as small as 2 microns so you can breathe comfortably. Washable pre-filter helps capture larger particles while also extending the life of the HEPA-type filter. Includes one Aer1 filter featuring the odor eliminating power of ARM & HAMMER Baking Soda and pre-filter. Optional ionizer assists in particle removal; 3 speed settings to keep air fresh and pure; Filter change reminder setting; Recommended for small rooms.