Cabin Air Filter. K&N Heavy Duty Cabin Air Filters replace your rig's stock cabin filter with a durable and reusable design that cleans and freshens incoming air. These robust cabin air filters help capture most mold, mildew, fungus, spores, bacteria, and germs controlling odors and contaminants inside the cabin during those long hauls. They are electrostatically charged to grab and hold dust particles. When they get dirty no need to replace, K&N's cabin air filters are incredibly easy to clean and reuse and best of all, they come with a 10 year / Million Mile limited warranty.