Large Three Layer Performance Air Filter:This 360-degree radial flow air filter features a 5" flange and our oil-free Pro DRY S media with three layers of synthetic media for maximum convenience. Its progressive layering provides great filtration efficiency and dust holding capacity, while not requiring the use of oils. This media is best suited for street and light off-road use. The filter features an injection molded base and top for lighter weight and rigidity. Its base includes a built-in 3-angle velocity stack for smooth, even airflow and captive screws to easily attach the filter to the housing.