After turning on the machine, just the pen tip vertically and lightly on the gemstone to be tested. After hearing the "beep" prompt sound, the real diamond light up indicators and make a sound. If there is no response, it is an imitation (such as cubic zirconia ()) The diamond tester pen distinguishes natural diamonds from other imitations by thermal properties. The detector accurately judge the authenticity of the gemstone through sound prompts of specific frequencies to avoid misjudgment of synthetic gemstones For gemstones of different sizes, the diamond tester provides intelligent adjustment function without the need for precise weight (1 green light is on when testing diamonds above 1 carat, 2 green lights are on when testing 0.5 carats, and 3-4 green lights are required for smaller gemstones) When metal or other materials with thermal conductivity close to diamond are detected, the diamond tester professional emit a special high-frequency warning sound. Please avoid testing on metal surfaces, skin or in humid environments. During the test, we must touch the panel on the back Including diamond detector, USB charging cable, test bench and detailed user manual. Diamond tester pen can easily identify the authenticity of various gemstones, and the testing process not cause damage to the gemstones Color: Black Material: Metal+Plastic Package Contents: 1 pcs * diamond tester pen Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.