The Airaid Pre-filter is a specially designed filter wrap made to extend the service interval of your Airaid or K&N filter when used in very dusty conditions. They are made from durable polyester material containing a uniform weave. The Airaid Pre-Filter will stop small dirt particles with minimal restriction to the airflow of the filter. The pre-filter is designed to be run dry and can be cleaned with the Airaid or K&N filter cleaner. The Airaid pre-filter is custom made to fit each application. Double stitched elastic openings assure that the pre-filter will stay in place. The Airaid pre-filters are available in a variety of sizes. If you don't see your filter size her please call us Toll Free at 1-866-820-2153.