aFe 21-91059 Momentum HD Pro Dry S Cylinder Shaped Air Filter Improves airflow for better performance and acceleration Oil-free for easy quick servicing and yet washable/reuseable air filter for long service life with life-time warranty Pro DRY S Three-Layer Progressively finer porosity synthetic media for high airflow with high filtration efficiency. Tall, Rounded, evenly-spaced pleats for maximum dust holding capactiy Constructed with 100% pliable polyurethane for great seal without use of foam gaskets or sealing grease.