PERFORMANCE AIR INTAKES Use the latest concept in air filtration technology Unique 2-part polyurethane foam material traps dirt and debris while letting air flow through Full-depth filtering system — interlocking cells coated in oil trap and hold the dirt through the entire volume of the filter Foam filters are made of far superior paper or gauze — they're 12 times thicker and continue to perform even as the filter gets dirty. And here's the best part....when the filter gets dirty, just wash and reuse! Will not void factory warranty. Lifetime warranty.