This True HEPA Filter is designed for use in Vornado True HEPA Air Purifiers. Using genuine Vornado air cleaner filters and replacing the filters at the recommended intervals will ensure you enjoy peak performance from Vornado Air Purifier. Replace your True HEPA Filter every year with continuous use, depending on your environment. Used in Vornado Air Cleaners to remove 99.97% of airborne irritants that pass through the filter including pollen, dust, mold spores, pet dander, smoke, odors and more. Maintain the health and comfort of you and your family. Vornado’s Automatic Filter Refill Program for Vornado Air Purifiers offer a convenient way to receive regular shipments of Vornado filters for your Vornado Air Purifier! Eliminate the hassle of remembering to reorder. Maintain the high efficiency of your Vornado Air Purifier by never running out of new filters. Receive FREE SHIPPING on all air cleaner filter refill orders when you set up a product subscription. Click the “Subscription Wizard” button above to set a customized schedule to receive your filters – conveniently billed automatically. This True HEPA Filter, part number MD1-0022, works with models AC300, AC350, AC500, AC550, PCO200, PCO300, PCO375DC, PCO500, and PCO575DC True HEPA Air Purifiers.