Retractable pin gages are specially designed for entry into hard to reach areas and for checking a variety measurement features. These gages require rests to locate on a datum face. In most cases, both the rest and movement require total retraction beyond the range of the readout to enter into recessed areas such as; under flange faces, spool cavities, or within deep grooves. These gages are used to check upper and lower “L” grooves, retaining grooves, and basic angular diameters from the datum surface, spherical radii, and other configurations. Companion part-simulating setting masters are also supplied upon request.