1.[Compatible Models] This premium MD1-0022 hepa filter replacement is specifically designed to fit Vornado MD1-0022 MD1-0023 AC300 AC350 AC500 AC550 PCO200 PCO300 PCO500 PCO375DC PCO575DC Air Purifiers. Please confirm your machine's brand and model before purchasing 2.[Powerful Three-Stage Filtration System] Our MD1-0023 H13 true HEPA filter is perfectly compatible with Vornado air purifiers. Fine pre-filter layer can effectively capture large particles of dust, hair and other impurities, prolong the life of the subsequent filter. The H13 HEPA filter can filter out at least 99.97% of 0.3 micron sized particles, such as pollen, pet dander, smoke. The activated carbon adsorbs odors in the air efficiently. This system for you and your family to create a fresh, y air environment, bring a comfortable experience 3.[Valuable Packages] Package includes 2 H13 true HEPA filter + 4 pre-filter. Size: 11.8 x 10.2 x 1 inches. Our MD1-0022 filter contains all the required parts to complete the standard installation of your Vornado MD1-0022 MD1-0023 AC300 AC350 AC500 AC550 PCO200 PCO300 PCO500 PCO375DC PCO575DC Air Purifiers 4.[Replace Regularly] It is recommended to replace your air purifier filter every 6-12 months to ensure that your air purifier has efficient filtration capacity. (depending upon your usage). Easy installation, no tools support