A temperature gauge is a mechanical or digital device used to measure and display the temperature of a fluid or gas in a pipeline, tank, or vessel. It uses a sensing element, such as a bulb or a thermocouple, that detects temperature changes and transmits this information to a display unit. Temperature gauges come in different types and sizes, with different accuracy levels and temperature ranges. Some temperature gauges are designed for low temperatures, while others are designed for high temperatures, such as those found in furnaces or boilers. They can also be designed for specific fluids or gases, such as those used in the chemical processing industry.