Momentum’s unique filter-to-housing interface was built to feature the largest air filter possible. This 360 Degree radial flow air filter features a 4 Inch 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 use. Its inverted top makes for more filter surface area, resulting in longer service intervals. This system features a high quality, computer-designed, dyno-tuned intake tube to achieve maximum power gains while maintaining a perfect fit. Its XLPE material is heat soak resistant and extremely durable.