A dial gauge is a precision measuring instrument used to measure small distances or variations in size. It features a dial face with a needle that indicates measurements on a graduated scale. Dial gauges are commonly used in engineering and manufacturing to check the accuracy of parts and ensure they meet specified tolerances. These gauges can measure linear dimensions, such as thickness or height, and are often used in conjunction with other tools like micrometers or calipers. They are valued for their ease of use and ability to provide quick, accurate readings, making them essential in quality control processes.