The indoor air pollution solution. The Homedics® TotalClean® Replacement HEPA-Type Filter features 360-degree HEPA-type filtration that removes up to 99% of airborne allergens as small as 0.3 microns*.Its built-in prefilter traps larger particles. And its activated carbon filter reduces household odors and VOCs**. Replace every 12 months (with normal usage) for optimal performance of Homedics® TotalClean® 5-in-1 Tower Air Purifiers (AP-T20/AP- T20WT).