A dial indicator is a precision measuring tool used to measure small distances or changes in position. It features a dial face with a needle that moves in response to a probe, which contacts the surface being measured. The dial typically displays measurements in millimeters or inches, allowing users to read the results easily. These instruments are commonly used in engineering, machining, and quality control to ensure parts are manufactured to exact specifications. By providing accurate measurements, a dial indicator helps detect deviations in alignment, flatness, or roundness, contributing to improved product quality and performance.