Calipers are a measuring tool used to accurately determine the distance between two opposite sides of an object. They are commonly used in engineering, machining, and woodworking, among other industries, to measure the dimensions of objects with high precision.

There are two main types of calipers: inside calipers and outside calipers. Inside calipers are used to measure the internal dimensions of an object, such as the diameter of a hole, while outside calipers are used to measure the external dimensions of an object, such as the width of a board.

Calipers can come in different shapes and sizes, but the basic design consists of two legs that can be adjusted and then clamped together to measure the distance between them. Some calipers have a dial or digital readout to provide a more precise measurement, while others may require the use of a separate ruler or measuring device to determine the exact measurement.