A Vernier caliper is a measuring instrument consisting of a fixed ruler in millimeters and a nonius or sliding scale. Using this instrument, we are able to measure interior spaces or diameters, thickness, length and exterior diameters, and depth in an object.
A micrometer is a nut and bolt mechanism that measures small distances or thicknesses between its two faces, one of which can be moved away from or towards the other by turning a screw with a fine thread.
We use these instruments to measure more precisely.
To practice how to read a measure in these instruments click on these links: