This filter features Pro-GUARD 7 oiled Five-Layer Progressively finer mesh cotton media with Two-layer Progressively finer porosity synthetic media for highest filtration efficiency for extreme dirty environments. The progressive layering of media allows the filter to flow at high levels even when dirty. This media is washable and reusable for multiple cleaning cycles and is designed for the most extreme environment. Rounded Open Pleats: aFe Power performance air filters use a tall, rounded, evenly spaced pleat design which produces more useable filter surface area for increased airflow and greater dust holding capacity. 100% polyurethane construction: To allow multiple cleaning cycles, the air filter is made with 100% 55 Shore "A" pliable polyurethane that does not deteriorate with time or exposure to heat and chemicals. Piable urethane ensures excellent sealing capacity without the use of foam gaskets or sealing grease. aFe Power OE replacement performance filters will not void the factory warranty and are emission legal in all 50 States.