True HEPA filter B is specially designed for use in the Holmes HAP756-U True HEPA Allergen Remover. This filtration offers enhanced mold-fighting power & helps remove 99.97 percent of particles as small as 0.3 microns. The design captures unpleasant odors & common allergens & pollutants, such as mold, dust, dust mites, debris, pet dander & smoke that may cause coughing & sneezing. The filter maintains consistent high performance over time. It is also compatible with HAP8650B-U, HAP9726B-U, HAP9726-U, HAP726-U, HAP633-U, HAP616B-TU & HAP616-TU. Replace it at least once a year.