Laser Hologauge LGH-1010-B-EH 542-720D Resolution .005mm Accuracy .1µm Range 10mm x .4"This is a highly precise dial gauge that uses optical interference so you can measure with unparallelled accuracy. The Mitutoyo Laser Hologage offers you the following benefits: Through optical interference of laser light through a diffraction grating it gives you an extremely precise holographic scale with 0. 005 m resolution. The measuring head is very compact, enabling you to build it into various systems far less expensively than conventional