Determine whether a surface’s flatness is within tolerance from an easy-to-read LCD screen. As you slide these gauges across surface plates, lapping plates, and other surfaces, they’ll quickly detect and measure any deviations. They come with a calibration certificate traceable to NIST that states they’ve passed a test for accuracy. Since they have zero-position memory, also known as absolute (ABS) positioning, they’ll retain their measuring position when they’re turned off. A zero-set button allows you to start measuring at any point.