Dial calipers have adjustable jaws that slide along a beam to measure between two opposite sides of a tool or part. The graduated dial displays simple and precise measurements of inside and outside lengths and diameters in inches or metric units. Calipers that measure outside diameters, inside diameters, and step and depth measurements are also known as 4-way calipers. Calipers with upper jaws take inside diameter measurements, and calipers with NIST-Traceable long form calibration certificates are used where traceability is required. They are commonly used in light and heavy manufacturing, production, machine and woodworking shops, or in applications where a high degree of precision is required.