In the full-scale automotive performance industry, (specifically RK-3946X ) identifies a specialized air cleaner assembly from K&N Engineering . Design & Build : Type : Round air cleaner with a flat base style. Size : 6 1/4 inch diameter.
: As part of the RK Series, it is designed to increase horsepower and torque by providing a less restrictive airflow compared to stock paper filters. In the full-scale automotive performance industry
K&N RK Series Air Filter Assemblies RK-3946X - Summit Racing In the full-scale automotive performance industry