K&N Intake System for Harley Davidson - Color (Red) - Style (Oval) - Size (9in)The K&N RK 3930 Air Intake System was designed to get more horsepower from your Twin Cam Harley Davidson engine. Built around the legendary K&N High Flow Air Filter, this RK Series assembly includes an innovative powder coated billet aluminum back plate that eliminates external breathers and features a built in, dyno tuned velocity stack. The result is a significant airflow increase to the engine without sacrificing filtration. This RK Series assembly