The Presidium Multi Tester III (PMuT III) utilizes the combined principles of Thermal and Electrical Conductivity from patented technology. The measuring probes, together with the electronics circuitries, are designed to pick up and segregate data collected from the stones via a customized micro-controller. It identifies metals, stimulants, moissanites and diamonds instantly. Within a split second the test result will be displayed. This tester includes surface mount technology, no waiting time between tests, 180-degree multi-viewing LED display, ergonomic design with rubberized anti-slip grip and auto power down. The retractable thermoelectric probe tip ensures accuracy and consistent pressure between the measuring probe and gemstone. Accurately tests on diamonds as small as 0.02ct. This tester runs on 3 AAA batteries (not included) or an AC adaptor (not included). Comes with a protective carrying case and measures 6-1/2" long.