Mallory Universal EFI High Performance Adjustable Fuel Pressure Regulator. Base pressure adjustable from 30-100 psi, 4 Port, Boost referenced design allows fuel pressure to rise on a 1 to 1 ratio with boost, supports medium (400 HP) to high horsepower (1700 HP) applications. Constructed from CNC-machined black anodized billet aluminum for maximum performance and durability. Can be mounted directly to the fuel rail or on clean area of engine compartment that is away from exhaust headers.