Replacement Filter for Levoit Air Purifier Core 400S Part Core 400S-RF H13 HEPA Filtration 5 Layers CAREFULLY CHECK YOUR MODEL NUMBER to be sure this is the right filter for your Air Purifier. This filter is compatible with air purifier models Core 400S, Core 400S-RF, and works just like the one that comes with the unit. Cost-Effective Price: Value pack saves much cost for your all year round air cleaning needs. Higher level filtration performance for long time using. It is recommended to replace filters every 6-12 months. Using an old filter lowers your air purifier's efficiency. H13 True HEPA Technology: A higher grade true HEPA material was used with 360-degree filtration, captures 99% of particles down to 0.3 micrometre in diameter. Improve your indoor air quality to breathe and sleep easier, avoid sniffles and sneezing. EFFICIENT ODOR REMOVAL: Activated Carbon Filter can filter various unfavorable odors and fumes, including volatile organic compounds (VOCs), tobacco smoke, and other household odors.