The Vintage N. C. K internal dial caliper gauge is a highly precise tool used for CNC inspection measurements in metalworking. This caliper gauge is specifically designed to accurately measure internal diameters, 0.001" RANGE 3-1/4 TO 4-1/4 INCH making it an essential tool for ensuring quality control in manufacturing processes. With its reliable measurements and durable construction, this vintage caliper gauge is a valuable addition to any CNC machining workshop.