Vornado MD1-0022 Replacement True HEPA Filter Contains one (1) genuine Vornado True HEPA Filter Fits Vornado air purifier models AC300, AC350, AC500, AC550, PCO200, PCO300 and PCO500 True HEPA Filter captures 99.97% of all airborne particles 0.3 microns or larger Vornado disposable True HEPA Filters require no cleaning Easy to replace, no tools required