Hoover Air Purifier with TiO2 Technology Here's what makes this Hoover so remarkable: It cleans the air by trapping 99.97% of dust and pollens down to 3 microns: Put it down plug it in select one of three cleaning levels set the timer for the desired run time and you're done. You'll begin to feel relief from dust dander and pollen. Easy clean multi-stage filtration that tells you when it needs it: The Hoover rinsable pre-filter is the first line of defense in the multi-stage filtration system. It catches lint pet hair and other large particles so the filter made with HEPA media can do its job. The pre-filter can be removed rinsed and replaced. When the HEPA filter requires changing an LED illuminates. Remarkable Odor Reduction: Smoke pets or anywhere that has an unpleasant odor is ideal for this Hoover Air Purifier equipped with an additional charcoal filter to absorb and eliminate airborne odors.