These are inline Bosch competition fuel pumps, and it is generally recommend they be installed between the factory (or another aftermarket) in-tank fuel pump, and the fuel rail. In addition, feeding these inline pumps with another pump (in series), will boost the output of the Bosch 044 fuel pump even higher.

Ltr/min @ 3 bar: 4.4
Lock Out (bar): 11.2
Input: 18 x 1.5
Output: Banjo