the Hqdz Diamond Tester Pen is easy to operate. Just turn it on, lightly press the tip to the gemstone, and wait for the beep to know if it's real or fake.If it's Real Diamond.The professional Diamond Tester will lighted up over 9 and emits audible sounds. No reaction means the stone is a fake crystal or simulant like cubic zirconium (CZ). up/down button, according to the number of carats displayed below the instrument adjustment, you do not need to set the exact number of carats.But remember, for diamonds (greater than 1.0 carats), please turn on 1 green light; For diamonds (0.5 carats), turn on 2 green lights. For small gems (such as cuts or cones), turn on 3-4 green lights. The high-frequency sound during metal testing is due to the test pen's operational principle, which relies on thermal conductivity to distinguish between diamonds and fake gemstones. Since metal possesses thermal conductivity similar to diamonds, it generates a high-frequency sound during testing. We have to choose the diamond size before using the diamond tester.Otherwise we may get the incorrect result.[Bare Hands Operation Touch Panel]: We have to touch the panel on the back when testing. Othersize we will get a wrong result The mini LED foldable magnifying is equipped with 30X 60X lens, portable and reliable for you to see the item you want to know, no worry about missing the details of gems; And you can also share them with your family members or good friends to enjoy much fun. 1. The preheating time is 1 minute. 2. When the instrument is turned on, it will automatically shut down without working for 3 minutes. 3. Easy to use: [Adjust Size]:We have to choose the diamond size before using the diamond tester.Otherwise we may get the incorrect result. [Bare Hands Operation Touch Panel]: We have to touch the panel on the back when testing. Othe