Calipers
Calipers are used to take inside, outside, and depth measurements
not requiring accuracy to a thousandth of an inch. Typical usages
include measuring valve springs, pistion diameters, and bearing
thicknesses. A graduated steel beam contains a fixed jaw with a
sliding scale.There are two types of calipers available for use in
automotive repair: vernier and dial. Either one may be capable of
displaying both English and metric measurements.