Pressure Gauge with Glycerine (LA, LBD)
Bourdon Tube Pressure Gauge | Liquid-Filled Pressure Gauge
Measurement of pressure which is called pressure gauge has been developed well for using in hydraulic system.
Instruments used to measure and display pressure in an integral unit are called pressure gauges.
A manometer is a good example as it uses a column of liquid to both measure and indicate pressure.
Likewise the widely used OMAX gauge is a mechanical device which both measures and indicates, and is probably the best known type of gauge.
Other methods of pressure measurement involve sensors which can transmit the pressure reading to a remote indicator or control system, it is called Silicone Filled Gauges.