Abstract: Electronic precision measuring instruments such as calipers, micrometers, and the like, are adapted for measuring odd and irregular shapes. The electronics are built into the measuring instruments to respond to a pinion gear rolling along a rack of teeth responsive to the movement of a movable jaw mounted on an arm having a stationary jaw and the rack of gear teeth associated therewith. A matched pair of adapters fit over and lock to the jaws. The adapters include a set of pins having lengths and shapes which may fit into and around unique spaces and structures. The adapter pins may be either confronting or opposing to enable either inside or outside measurements.