This is a military qualified MS14 GPS splitter with one-input and four-outputs. It typically finds application where an input from an active GPS roof antenna is split evenly between four receiving GPS units. 

The MS14 can be configured to pass DC from an RF output (J2) to the antenna input port (J1) in order to power an active GPS antenna on that port. The remaining RF outputs (J3, J4, and J5) would feature a 200 Ohm DC load to simulate an antenna DC current draw for any receiver connected to that port.