This is a good used FMU that was removed from a Mustang with a Vortech Supercharger when it was restored back to stock. Unlike most standard FMU's this one is adjustable.
 
The fuel management unit is designed for use on multi-point electronic fuel injected engines. It is a secondary fuel regulator that installs in series with a stock regulator on the return line to the tank. The unit increases fuel pressure in proportion to boost pressure (this assumes the pump being utilized is of sufficient pressure and flow to deliver the fuel required). This is great for cars going boost on a low budget or has a lack of engine management support via ECU retuning. Because it is a mechanical based unit, no special electronics are needed to run this unit. It is very straight forward to install. 
A FMU is used on fuel injected, supercharged, and turbo engines using the factory electronic engine management system. When boost pressure is present, this unit will raise or lower your fuel pressure in proportion.