Indicating disc gages are used to measure I.D.s or O.D.s around shafts and other obstructions such as grooves, stepped areas or boss type obstacles in the shaft area or any other configuration that prevents the use of a standard snap, bore or straight frame shallow diameter gages. Indicating disc gages feature the principle of two point measurement and fixed centralizing locators. Most disc gages are made for a specific size or can be used with 1/4" adjustment contacts to span a variety of sizes.