The K&N RK-3943 High-Flow Air Intake System increases engine intake airflow and delivering more horsepower & torque to certain Harley-Davidson XL1200 model motorcycles. The intake system increases power by eliminating the stock OE air cleaner and replacing it with a complete High-Flow Air Intake System. The sturdy, custom aluminum backing plate mounts directly to the throttle body via an aluminum integrated, internal-run breather system. The intake system comes with a K&N Air Filter for high air flow and long service intervals. The K&N High-Flow Air Filter is washable, reusable, pre-oiled and ready for installation.