The Aeromotive Billet Digital FMU is a fully adjustable, scalable electronic FMU designed specifically for returnless fuel systems. The Aeromotive FMU senses manifold pressure and automatically provides the fuel pressure that you dial in, maintaining proper air/fuel levels at all operating conditions. When used in conjunction with an external fuel pump, the FMU will allow a supplemental pump (sold seperately) to provide the proper volume thereby increasing the system pressure. The FMU is scalable and completely adjustable to provide increased fuel pressure levels at any boost. The unique part about this FMU is that it has the ability to provide ''any'' fuel curve throughout the power range. It also features LEDs that are tied to a scalable rotary knob. This allows you to create a fuel pressure that corresponds to your boost curve. The housing is made of billet 6061-T651 aircraft aluminum alloy and is finished with a bright dip red anodize.