ONE Smarts' OSAP01 and OSAP02 Smart Air Purifiers uses OFAN-01 HEPA filters. OFAN-01 is a 3-in-1 Air Purifier Filter. The first layer Pre-filter catches large particles such as hair, dust and pet dander. The second layer is a True HEPA Filter and works as an air sanitizer. The filter for air purifiers removes air pollutants such as: viruses, pollen, allergens, bacteria, dust mites, gases, cigarette smoke and many more. The third layer is the Active Carbon Filter, absorbing odors, benzene, and formaldehyde. The Air Filter provides high quality air filtration by removing 99.97%. The HEPA Filter is highly efficient and provides a better breathing environment.