ADD W1  Billet Aluminum Adjustable Fuel Pressure Regulator provides you with the ability to adjust fuel pressure for maximum efficiency and horsepower gains. Factory regulators are not adjustable and wear out over time due to weakening internal spring tension which reduces power and mileage. Stock vehicles with high mileage can restore lost power by simply replacing the regulator and performance built motors benefit from the ability to precisely meter fuel delivery. The Regulator is a direct replacement and features. adjuster to prevent stripping unlike other designs. Precision machined out of billet aluminum