These fuel pressure regulators feature a unique design that allows it to be mounted directly to the fuel rail, taken out the hassle of trying to find a mounting place in the engine bay. It features a compact push-in style design with a swivel style mounting bracket, so that it can be clocked in various directions to fit your setup. They are used in Edelbrock Pro-Flo 3 EFI systems and can be used with any -6 AN fuel rail.