Keep your air purifier working like new with the genuine Homedics 3-in-1 True Hepa Replacement Filter. It removes up to 99.97% of airborne allergens as small as 0.3 microns and features a built-in prefilter that traps larger particles. Plus, an activated carbon filter to reduce household odors. Performance is best when the filter is replaced every 12 months. Compatible with Homedics Air Purifiers, models Ap-T100.