The True HEPA Replacement Filter R captures 99.97 percent of airborne particles as small as 0.3 microns to help you establish a cleaner breathing experience for you and those around you. Plus, its advanced design delivers cost-efficient performance by providing up to one year of filtration before replacement is required. Replacement Filter R is designed for use with Honeywell HPA090 series, HPA100 series, HPA200 series, HPA250 series, HPA300 series, HPA3100 to HPA3300 series, HPA5100 to HPA5300 series and HPA8350 series air purifiers (sold separately).