The Lot of 4 Medify Air-x Air Purifier HEPA Filters are flat panel filters designed specifically for air purifiers. Manufactured by AIRx Filters, these HEPA filters are essential for maintaining indoor air quality and purifying the air in your home or garden. With a pack of 4 filters, you can ensure that your air purifier is continuously operating at its best to remove allergens, dust, and other pollutants from the air.