Die Cast Aluminum Construction. Adjustable from 4.5 – 9 PSI for precise fuel pressure adjustments. Used in return style systems with a line back to the fuel tank. 3/8 NPT Inlet, Outlet, and Return Ports. 1/8 NPT Gauge Port and Earl’s Fuel Pressure Gauge (100187ERL). Gasket 3/8 NPT to -6 AN fittings (481666-BL x3). If a product does not meet your expectations, please permit us the opportunity to fix the issue before leaving feedback. A satisfied customer is our #1 priority!