K&N Street Metal Air Intake Systems for Harley Davidson Dyna, Softail, Touring and Twin-Cam Model motorcycles increase power by eliminating the restrictive stock OE air cleaner and replacing it with an oversized K&N High-Flow Air Filter and a cast aluminum high-volume aluminum housing. K&N high-flow intake systems give your Harley an aggressive appearance while providing a significant increase in airflow resulting in more power.