Motorcraft Cabin Air Filters help keep the air flowing through the HVAC system clean and free from harmful particulates. Why Buy: -Air filters should be replaced every 12 months or 15,000 miles - check Owner's Guide for specific recommendations. -Electrostatically charged layer captures soot, smog and tobacco smoke. -Particulate layer protects HVAC components by restricting dust, mold spores, pollen and fungus. -Reduces dust inside the vehicle. -Captures 90% of particles 10 microns or larger (for comparison, an average grain of sand at the beach is 200 microns). -Dual layer construction with a meltblown layer that contains fibers that capture sub-micron particles. -Rigid polyester spunbound material used for frame, in most models, the framing material is laminated with a lofty polyester layer to help reduce unfiltered air by-pass. -Materials meet Ford Engineering requirements for resistance to odor propagation and anti-microbial properties.