Holley 12-803BP Fuel Pressure Regulator
This fuel pressure regulator is used to adjust to fuel pressure requirements of various carburetors.  It includes 3/8" pipe thread inlet and outlet ports and fits systems with a return line back to the fuel line.  It allows for quieter operation and has a pre-set pressure of 7 PSI with a range of 4.5 to 9 PSI.