When it was first developed in 1962, the K&N Filtercharger® was a true design breakthrough in air filtration technology. Today, it still is. Because K&N's Filtercharger® can actually double air flow, which, in turn, adds up to 15 extra horsepower. The secret lies in the K&N Filtercharger® 's unique design. Conventional filters use paper or foam material permeated with millions of tiny, irregular passages, that screen dirt particles out of the air. Because the dirt particles are trapped inside the passages, they eventually clog; and when this occurs, airflow restriction increases dramatically. With the Filtercharger®, a special cotton fabric is sandwiched between the pleated aluminum screen wires. The pleated design provides five times more filtering surface over the element circumference. The cotton/screen wire filter media is then saturated with a formulated air filter oil. Acting like a fluid curtain, this oil attracts particles of dirt and debris which build up on the outside of the filter. This buildup of dirt particles suspended in oil creates more and more irregular passages that actually create an additional filtering barrier with use. In most cases, up to 1/8" of dust can cover a Filtercharger® before performance is significantly affected. On a street driven vehicle, a Filtercharger® can last up to 50,000 miles before service is required. Then, because it's made of reusable materials, you can just clean it, apply fresh K&N Filter Oil and re-install. Of course, K&N has developed biodegradable cleaning products designed to effectively clean the filter without harming the environment through the absence of fluorocarbons. More air flow, increased horsepower, long lasting performance ­ even after 35 years, the K&N Filtercharger® is still on the cutting edge of air filtration technology.