These mechanical outside micrometers are the standard/classic micrometer design for most high-precision outside dimension measurements when higher resolution than a caliper is required. Operators open the jaw with the thimble and insert a workpiece between the measuring faces and close the jaws. The main scale is then read and then added to the graduations on the vernier scale to provide the exact measurement. They are commonly used to measure the outside dimensions of raw materials, whole workpieces, and features in production, QA, and inspection environments in both metalworking and other industrial applications.