aFe MagnumFORCE Stage-2Si CIA System w/ PDS Filter 12-15 Porsche 911 Carrera S (991) 3.8/3.8LDual 360 degree radial flow air filters feature our oil free Pro DRY S media with three layers of synthetic media for maximum convenience. Their progressive layering provides great filtration efficiency and dust holding capacity, while not requiring the use of oils. This media is best suited for street use. Their inverted tops make for more filter surface area, resulting in longer service intervals. The smooth housing, constructed of cross linked