The Mitutoyo 534 series long jaw vernier caliper has two-way measurement capability for outer diameter (OD) and inner diameter (ID) in metric units, with long jaws for performing hard to reach measurements.

The calipers have a dual vernier scale, with both the upper and lower scales measuring in metric, and each graduated to 0.02mm. The scales are raised to slide easily and protect the graduation markings. A clamping screw on the upper scale rotates to control scale movement and locks to hold the sliding jaw's position. The caliper is made of hardened, corrosion-free steel construction with a satin chrome finish. Rounded measuring faces on the jaws help support accurate inner diameter readings.

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, machining, manufacturing, carpentry, and medicine. 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 all 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 dial caliper is used for measuring size differential between two objects, as well. The digital caliper takes the same sort of differential measurements as the dial caliper by zeroing the display at any point along the slide, with an LCD (replacing the dial) that displays a single, easily read value in both English and metric units. Some digital calipers can hold data readings between measurements and send them to data collection devices.

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.