A vernier calliper is a precision measuring instrument used to measure lengths up to 15 cm with high accuracy.

It consists of a main scale and a vernier scale, which allows readings with a precision of up to 0.01 cm or 0.1 mm.

Components:

External jaws to measure the outer diameter or width of objects
Internal jaws to measure the inner diameter of hollow objects
A depth rod to measure the depth of containers or holes
Therefore, vernier calipers are used in physics labs for accurate measurement of length, diameter, and depth in experiments requiring fine precision.