HP Billet Carbureted by Pass Fuel Pressure Regulator Return Size 3/8 Inch NPT Street/strip Carbureted Applications Two Port Adjustable from 4.5 to 9 PSI HolleyHolley Billet Fuel Pressure Regulators are part of a complete line of fuel system products from Holley. They are precision machined from 6061 T6 billet aluminum for strength and durability. They feature a black bright dip anodized body and a clear bright dip anodized top for corrosion resistance and good looks. The Holley 12 841 fuel pressure regulator features 3 8 inch NPT in out ports and a 3 8 NPT return port. Features and Benefits: Adjustable from