A pressure gauge is a device used to measure the pressure of gases or liquids in various systems. It provides a visual indication of pressure levels, helping users monitor and control processes in industries such as manufacturing, automotive, and HVAC. Pressure gauges can be analog, featuring a dial and needle, or digital, displaying readings on a screen. These instruments come in different types, including bourdon tube gauges, diaphragm gauges, and digital gauges, each suited for specific applications. Proper calibration and maintenance are essential to ensure accurate readings and safe operation in systems where pressure is critical.