The Gracer Airinx represents the first new "science" in air filters in years. To provide maximum air flow and filtration, we start with a bigger filter. The Airinx has a high-capacity wire mesh outer shell and an inner funnel of high-quality, lightweight ABS rosin. The primary filtering medium is a washable urethane. No "pre-oiling" is necessary. Two densities protect the turbocharger and engine from damaging dirt and debris. Dyno testing has shown consistent horsepower increases.