Contact-type precision measuring instrument used for dimensional measurement of machined parts and positioning accuracy verification of machine tools. Available in dial and digital types, capable of measuring minute displacements and dimensional differences in units of 0.01mm to 0.001mm. Essential measuring tool for machining accuracy verification on lathes and milling machines, jig and fixture alignment, straightness and flatness inspection of parts, and equipment centering operations. Used in combination with magnetic stands or dial gauge stands to perform dimensional management of narrow spaces and complex-shaped parts that are difficult to measure with calipers or micrometers.