Compatibility:Fits for NAPA 6637, for Donaldson B085011, for Baldwin PA2818, for Fleetguard AH1141, for FRAM CA6818, for WIX 46637 air filters. High Quality Material: The main material is polyester fiber, which has high strength and elasticity recovery, sturdy and durable, anti-abrasion, non-sticky lint. Function: Prevents dust, debris, and large particulate contaminants from causing blockages, enhances airflow, maintains filtration efficiency, and extends the service life of air filters. Reusable: Can be cleaned with just water and soap for repeated use. Package includes: 2x Pre-filter Sleeve (air filter not included) Air Pre-Filter Preclean Sleeve