FEATURES * Medical Grade Filter: A True HEPA filter is able to remove up to 99.97% of airborne particles down to 0.1 microns, like dust, pollen, smoke, odors, and pet dander. * 3-Stage Filtration: A pre-filter traps dust and hair, a carbon filter traps and removes odors, and the HEPA H13 filter removes the tiniest of particles from the air--all so you can breathe cleaner air! * Size Does Matter: Thanks to a larger surface area from the cylindrical design, our replacement filters are able to capture more airborne particles than flat filters. * Longer-Lasting: Depending on the average daily use, the AGH550 medical-grade filter can last up to 6-8 months. * Easy to Replace: Simply unwrap the plastic packaging and insert the new filter into your air purifier. After installation, press and hold the TIMER & FAN buttons for 5 seconds to reset the change filter reminder. WHEN? * Replacing the air filter every 6-8 months is recommended for optimal use (or according to your air filter status). * It is time to replace the air filter when the following signals appear: Increased noise, Decreased airflow, Clogged filters, Presence of odors from the unit. HOW? * Unplug the air purifier and remove the front shell. * Remove the old filter and then unwrap the new air filter. * Install the new filter and make sure the pull-tab on the filter is facing outward and put the front shell back. * Press and hold the FAN and TIMER button simultaneously for 3 seconds to reset the unit. Then the replacement reminder will be off. Frequently Asked Questions * What's a True HEPA Filter? HEPA stands for High-Efficiency Particulate Air. HEPA filters, originally designed by the U.S. Army to remove radioactive materials from the air, are the most effective way to remove pollen, dust, and other indoor particle pollutants. A True HEPA filter can remove 99.97% of airborne particles 0.3 microns or larger-- that's 166 times smaller than a human hair. Sometimes, you may see some filters named HEPA-like or HEPA-style, or HEPA-type. Unlike true HEPA filters, these filters cannot actually remove 99.97% of bacteria down to 0.3 microns in diameter. * What’s the difference between HEPA and Medical Grade HEPA Filter? Generally speaking, the higher the HEPA filter grade, the better the purification effect. True HEPA filters usually range from H10-H12. And the highest grade of HEPA filter is H13-H14, which is considered to be medical grade. A normal HEPA filter (H10-H12) removes 99.