HIGH-FLOW AIR FILTERS Never buy another filter—comes with one million mile warranty! Superior filtering PLUS maximum airflow EQUAL more HP and improved throttle response! These replacement air filters offer revolutionary technology that delivers 30, 40, sometimes 50% better air flow than stock filters. The more air flow to the engine, the more power you get. Filter consists of 4 layers of cotton gauze between 2 layers of metal screen. Cotton is much less restrictive than paper elements and is oil impregnated to capture the tiniest dust particles while allowing air to flow freely. Filters are washable, re-usable. To restore maximum air flow efficiency, order service kit (sold separately). All K&N® air filter elements are warranted against defective materials or workmanship for one million miles or ten years, whichever comes first.