Micrometers (Screw-Type Gage) use a screw thread to make accurate and repeatable precision measurements.
Come in metric or inch, size ranges, with or without vernier. Digital or analog.
On many metric micrometers, the barrel scale is graduated in half millimeters and the dial reads to the nearest .01 mm.
Vernier Scale on Micrometers
Some micrometers add a vernier scale to increase their resolution.
Screw Thread Micrometer
Caliper Type Micrometer