Calipers are precision measuring tools used to determine the dimensions of an object. They can measure internal and external dimensions, as well as depths. Common types include vernier calipers, dial calipers, and digital calipers, each offering varying levels of accuracy and ease of use. Typically made of metal or plastic, calipers feature two arms that can be adjusted to fit around or inside an object. The measurements are read from a scale or digital display, making them essential in fields like engineering, woodworking, and metalworking for ensuring precise measurements.