1511D Bionaire Air Cleaner Dual Filter Cartridge (4 Pack) Fits Bionaire models F150, F150s, F150w, F155, and FE1560. Bionaire dual air filter cartridges (Four Pack). Measures approximately 7 3/8 x 8 1/2 x 3/8. Removes sub-micron sized pollutants such as pollen, dust, smoke particles, and reduces bacteria while helping remove odors. For optimum performance, replace filter every 3 to 6 months or as indicated by the filter condition monitor.