The Mitutoyo 522 Diamond Master vernier caliper has flush-fitted main and vernier scales to help reduce parallax errors in reading outer dimension (OD), inner dimension (ID), depth, and step measurements in both inch and metric units, for applications requiring high levels of accuracy, especially in scientific research and in industries where parts must fit exactly.

The caliper has a dual vernier scale, with an upper scale graduated to 0.001€ and a lower scale graduated to 0.02mm and accurate to + or - 0.03mm. The main scale is octagonal in cross-section; it is flush-fitted with the vernier scale to help reduce parallax errors. The scales are raised to slide easily and protect the graduation markings. A thumbwheel permits fast and easy measuring. A clamping screw on the upper scale rotates to control scale movement and locks to hold the sliding jaw€s position. It has two sets of jaws and a depth bar for four-way measurement capability: outer dimension (OD), inner dimension (ID), depth, and step, where the butt end of the fixed jaw measures one end of a work piece before its upper/lower or inner/outer "steps" are measured. The caliper is made of hardened, corrosion-resistant stainless steel with a satin chrome finish that helps reduce glare. The caliper meets Federal Accuracy Specifications GGG-C-111B.

Calipers measure the distance between two opposing sides of an object. They make inside, outside, depth, or step measurements, according to their type. Calipers are commonly used in architecture, metalworking, mechanical engineering, and machining. The simplest calipers have two legs to mark the two points and require a ruler to take the measurement. More complex calipers use two sets of jaws instead of legs and have up to two graduated scales. Vernier, dial, and digital calipers give direct and accurate readings and are functionally identical, having a calibrated scale with a fixed jaw, and another jaw with a movable pointer that slides along the scale. The vernier caliper has a scale sliding parallel to the main scale for an additional, fractional reading to improve measurement precision. The dial caliper has a circular dial with a pointer on a toothed gear rack replacing the second vernier scale. As with the vernier, this second measurement is added to the reading from the main scale to obtain the result. The digital caliper takes a differential by zeroing the display at any point along the slide, with an LCD that displays a single value in English and/or metric units.

Mitutoyo manufactures precision measuring tools, metrology equipment, and systems. The company was founded in Tokyo in 1934 and formed Mitutoyo America Corporation in 1963, which is headquartered in Aurora, IL.