Keep your home purification system in tip-top shape by replacing the air filters every 3 to 4 months or 2000 hours. This air purifier replacement filter pack is compatible with the Medify Air MA-14 air purification systems only (unit not included). Designed to keep your air clean, these air filters are a higher grade of HEPA. This means the filter removes 99.9% of particles down to 0.1 microns. This air purifier filter pack also uses a 3-stage system with a washable pre-filter, HEPA H13 media to eliminate harmful particles, and an active carbon filter that removes unsavoury odors throughout your home.