A Bourdon tube is a mechanical device used to measure pressure. It consists of a curved, hollow tube that straightens when pressure is applied inside it. This movement is then translated into a reading on a dial, allowing users to monitor pressure levels in various systems. Bourdon tubes are commonly found in pressure gauges and are used in industries such as automotive, manufacturing, and HVAC. Their design is simple yet effective, making them a reliable choice for measuring both gas and liquid pressures in a wide range of applications.