The K&N PreCharger® filter wrap is specially designed to extend the service interval of your K&N Filtercharger filter when used in very dusty conditions. They are made from durable polyester material containing a uniform weave. The PreCharger will stop small dirt particles with minimal restriction to the airflow of the filter. This product wraps your air filter with an additional pre-filter Extends service interval of your K&N filter in dusty conditions Durable polyester material with stitched elastic openings Cleanable with K&N Filter Cleaner