An ID gauge is a tool used to measure the internal diameter of a tube or pipe. It is also known as an inside diameter gauge, bore gauge, or caliper. ID gauges are used to measure the diameter of a bore, or the inside of a tube or pipe. The ID gauge is used to measure the inside diameter of a tube or pipe, which is the distance from one side of the tube or pipe to the other. ID gauges are used in a variety of industries, including automotive, aerospace, and manufacturing. They are used to measure the diameter of a bore, or the inside of a tube or pipe, to ensure that the correct size is used for the application. ID gauges are also used to measure the wall thickness of a tube or pipe, which is the distance from the inside to the outside of the tube or pipe. ID gauges are available in a variety of sizes and styles, and can be used to measure both metric and imperial measurements.