Calipers are used to measure the distance between two opposing sides of an object in a variety of ways. These great devices come in a range of types, with three very common versions—Vernier caliper, digital caliper, and dial caliper. A Vernier caliper is the most common of all, and the most precise. A Vernier caliper includes a built in Vernier scale, which is a visual aid that indicates specific gradations between measurement marks. Utilizing a Vernier scale for measurement allows for an incredible degree of accuracy. A digital caliper is distinguished by the digital readout screen that displays the final measurement after the caliper has been adjusted appropriately.
Finally, a dial caliper is built with a small dial in place of the Vernier scale. The dial is rotated when taking a measurement and the final number will be in millimeters or inches, as read along the manual scale provided.