The station or static magnetometers are remote field passage indicators, which allow the operator to track the pig through sections of line. These units not only indicate the pig's arrival at that point, but indicate also the time of the event. An output from the unit can also give a relay closure, thus providing for any number of ancillary devices, i.e. radio telemetry, sona-alert, or input into the clients' SCADA network. Normally, indication is facilitated by high intensity strobing beacon, which can be seen from long distances especially from the air, and at night. The station indicators may take the form of either portable or permanent installations, or in marine applications, be sub marine or buoy mounted.