A dial gauge is a precision measuring instrument used to measure small distances or variations in thickness. It features a dial face with a needle that indicates measurements on a graduated scale. Dial gauges are commonly used in mechanical engineering, manufacturing, and quality control to ensure parts meet specified tolerances. These devices can measure linear dimensions, such as the height of a surface or the depth of a hole. They are often used in conjunction with other tools, such as calipers or micrometers, to provide accurate readings in various applications, including machining and assembly.