Cabin Air Filter. K&N Cabin Air Filters replace your vehicle's stock cabin filter with a reusable design that cleans and freshens incoming air. They are electrostatically charged to grab and hold dust particles. K&N cabin air filters help control odors while they help capture most mold, mildew, fungus, spores, bacteria and germs. When they get dirty they can be cleaned and reused and best of all, they come with a 10 year/1,000,000 mile limited warranty.