Outerwears Pre-filters are designed to keep out particles of dirt, sand, and street debris as small as .005in.  These Pre-filters are run dry, meaning no oils or additives are required so there is no dirt sticking to the oil and creating a premature loss of airflow and horsepower.  Outerwears water repellent Pre-filters add another level of protection. The woven mesh is specially treated at the mill using a proprietary process to repel water. This hydrophobic water repellent process is not sprayed on; consequently there is no airflow loss. Our Pre-filters are used and recommended by top professional engine builders and race teams worldwide.  Package includes 1 Outerwear…