Telescoping gauges and sets are used to determine the inside diameter of a bore or hole. They are inserted into bore holes and controlled by a knurled knob or small handle that expands the telescoping arm or arms until the spring-loaded plungers make contact with the sides of the bore. The gauge is then locked in place and removed from the hole. Then the distance between the contacts is measured with an outside micrometer. These gauges do not perform direct readings and do not have a dial or digital display. They are an accurate and commonly used in job shops and small and medium sized machine shops and production.