Claritin CAP529-U True HEPA Permanent Filter Tower Air Purifier, 20-Inch, White PERMANENT True HEPA filter helps remove up to 99.97% of airborne particles as small as .03 microns 5 clean settings includes a Super Quiet and Super Clean setting Dual Position Operation, sleek and versatile design allows for vertical or horizontal use Programmable timer runs up to 12 hours Filter Maintenance Button, lets you know when the filter should be changed Optional Ionizer, binds negative ions with airborne smoke, dust and pollen to form larger particles that are more easily captured