Rotary precision measuring instrument specialized for accurate dimensional measurement of parts' outer diameter, inner diameter, and thickness in manufacturing environments. Achieves high-precision measurement of 0.01mm to 0.001mm units by clamping the measurement object between spindle and anvil and rotating the thimble. Classified by application into outside micrometers, inside micrometers, depth micrometers, and thread micrometers, essential for quality inspection of machined parts, dimensional management of molds, and wear measurement of cutting tools. Used as standard intermediate measuring equipment in manufacturing quality control, offering higher precision than calipers without the complexity of coordinate measuring machines.