Murphy 4-1/2 inch (114 mm) diameter dial pressure Switchgauge instruments accurately and reliably measure and indicate pressures in applications such as gas compressors control panels, pumping applications, industrial process applications, etc. The Switchgauge versions incorporate adjustable switch contacts which operate in unison with the indicating dial readout to operate alarms, shutdown or automation processes. The 45PE series is a variation of our OPL series and has 2-SPDT snap-acting switches instead of the pointer type contacts of the OPL. Contacts are adjustable from the face of the 45PE. The 45PE is widely used for electric motor applications however can be used for engine applications.