Ready to measure right out of the box, no programming. Open jaws with the smooth-feel thumb wheel and read the LCD display. No reading "between the lines!" If you want to compare dimensions, reset the zero anywhere on the scale, caliper will give plus/minus readings. Close and reset zero and it's a regular caliper again. Graduations also marked on the beam for a quick manual check. No rack and pinion to get dirty, no delicate glass scale. 6" model bears the brunt of your measuring around the home and shop. 8" version cover those bigger specialized projects like measuring .50 BMG cartridges. Reads to .0005"/0.01mm; (Five, TEN thousandths). Accurate to .001" (0.02mm). Mfg: Mitutoyo SPECS: 9-1/16" (23.1cm) overall. Stainless steel. Plastic hard case; includes battery.