A caliper is an instrument used to measure the distance between two symmetrically opposing sides of an object.Calipers are used to measure objects which cannot easily be measured with a ruler or other measuring instrument.
The jaws of the caliper are adjusted so that the tips fit across the points to be measured.
Some calipers, like spring-joint calipers, require another measuring tool such as a ruler to measure the distance between the measuring faces.These calipers are also known as transfer measuring tools.
Other types of calipers such as digital calipers, dial calipers and vernier calipers have a scale as one of their key components.Measurements are read straight from the display on the caliper, so that a secondary measuring instrument is not needed.
Calipers are mechanical engineering tools that tend to be associated with metalworking.
However, they are also used in a number of different fields including gunsmithing, woodturning and woodworking.