Holley Billet Fuel Pressure Regulators are just part of the complete line of fuel system products that Holley offers, his regulator is constructed from 6061-T6 billet aluminum for strength and durability, Adjustable from 4-65 psi and will handle both carbureted and EFI applications, So, if you are currently running a carbureted system but plan to upgrade to EFI in the future, this regulator will have you covered either way, Used in systems with a return line back to the tank.