A pressure gauge is used to measure the pressure between two specific points in a flowing stream. It is very important to use a pressure gauge at the inlet and outlet of the screen filter to measure the pressure drop and also keep a check on the nature of the flow. Pressure gauges come at various ranges depending on the pressure range required. The pressure gauge displays the change in pressure in two units viz. psi(pounds per square inch) and kg/cm2 (kilogram per sq. centimeter)