This filter features seven layers of composite media for maximum protection. The patented combination of oiled cotton gauze with synthetic material allows this media to thrive in the dustiest and dirtiest environments imaginable. Pro-GUARD 7 filters are easily recharged with aFe POWER CLEANER and gold air filter oil. aFe POWER performance air filters use a rounded, evenly spaced pleat design which allows for more usable filter surface area, providing increased flow and greater dust holding capacity. This aFe POWER performance air filter is constructed with a polyurethane base and top. Unlike other materials that degrade after repeated heat cycles in an engine bay, polyurethane maintains its original molded shape.