The Mitutoyo 515-570 depth micro checker is a reference gauge that supports checking the zero point of a depth micrometer in the range of 0 to 150 mm. The accessory is used to make confirmation reference measurements in increments of 25 mm with a metric depth micrometer up to 150 mm for verifying and adjusting the micrometer’s base zero position. Depth micrometers measure the height or depth of any shape that has a step, groove, or slot.The depth micro checker measures 180 x 72 x 72 mm (H x W x D) and has reference measuring blocks laddered every 25 mm against which confirmation measurements can be made. Block pitch accuracy is + or - (1+L/150) micrometers (0.001 mm), where L is the length to check from 0 to 150 mm, in 25mm increments. The anvil block accuracy is + or - 0.5 micrometers. The unit weighs 6.6 lbs (3.0 kg), and comes with a certificate of inspection.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.