The Stahlwille 12900N stainless steel inch/metric vernier caliper has a 6"/150mm measuring range, 1/128"/0.05mm graduations, and four-way jaws for measuring the inside diameter (ID) and outside diameter (OD) of holes, grooves, and tube thicknesses, and depth and step measurements of bores and grooves. A thumb lock holds the measurement in place for accurate reading. Hardened stainless steel construction provides durability and wear resistance. The caliper includes a plastic pouch. Vernier calipers are measuring instruments commonly used for inspection in manufacturing to provide the precise measurements of an object. A pair of jaws attached to a long beam with a marked scale is used to take inside, outside, and step measurements. An additional depth probe slides along the beam to take depth measurements. One jaw is fixed to the end of the scale, while the other jaw slides along it with gearless precision to take measurements. The main scale is engraved directly on the beam while the vernier scale is engraved on the slider mechanism. The base measurement is taken from the long beam, which provides the initial whole measurement in inches, centimeters, or millimeters. To obtain the total measurement, the base reading is added to the vernier scale reading, which provides fractional measurements in inches or millimeters. A locking mechanism provides the ability to take differential measurements for determining the difference in measurements between two objects. Compared to digital and dial calipers, vernier calipers are more durable because they do not have internal moving parts, and are less prone to inaccuracy caused by shock, debris, and other contaminants, but they can be more difficult to read than digital and dial calipers. Vernier calipers are commonly used in fields such as metalworking, mechanical engineering, machining, and carpentry.Stahlwille manufactures hand, power, and measurement tools such as socket sets, air impact tools, calipers, and electromechanical torque wrenches for the automotive, aerospace, energy, and manufacturing industries. The company, founded in 1862, is headquartered in Wuppertal, Germany.What's in the Box?Stahlwille 12900N stainless steel vernier caliperPlastic pouch