Hydraulic instruments are devices that use fluid mechanics to measure or control pressure, flow, and other properties of liquids. They operate based on the principles of hydraulics, which involve the movement of fluids in confined spaces. Common examples include pressure gauges, flow meters, and hydraulic presses. These instruments are widely used in various industries, including construction, manufacturing, and automotive. They help ensure safety and efficiency by providing accurate measurements and enabling precise control of hydraulic systems. Understanding how hydraulic instruments work is essential for maintaining equipment and optimizing performance in fluid-based applications.