Midwest 140 Series Differential Pressure Gauge is a diaphragm type pressure gauge that measures differential pressure through a flexible elastomer diaphragm and a calibrated range spring. The diaphragm assures total separation between the high and low pressure signals. A magnetic coupling transmits the sensing element motion to the indicating pointer. This prohibits the possibility of process fluid leaking into the gauge case, while assuring total isolation of the process fluid within the pressure capsule.