Intuitive Design, Fast and Safe - Our diamond tester comes with an LCD display and LED indicators to easy to read accurate test results.This diamond selector is designed for fast, accurate and safe diamond testing, ensuring no harm to the diamond during the test.Provide accurate results every time.It is popular among professionals, amateurs, coin lovers and business owners.Excellent tool. for money. Good gifts. Easily Test - Key operation, easy to see.No professional required - Diamond Test Pen is easy to operate. Simply turn it on, gently the tip to the gem, and wait for the beep to know if it is true or false.If it's a real diamond.Professional diamond testers light up more than 9 and make sounds.Non-responsive means that the stone is imitation crystal or similar cubic (). Key , easy to use - Please place the tip of the pen vertically and gently on the test stone.Please adjust according to the size of the gem you want to measure.The instrument up/down buttons adjust the number of carats displayed below according to the instrument, you do not need to set the exact number of carats. But remember, for diamonds ( 1.0 carats), turn on 1 green light; for diamonds (0.5 carats), turn on 2 green lights.For small gems (such as cutting or cone), turn on 3-4 green lights.(Please be careful not to touch the keys of the instrument during testing) High frequency sound during metal testing - High frequency sound during metal testing is due to the operating principle of the test pen, which relies on thermal conductivity to distinguish between diamonds and fake gemstones.Because the metal has a similar thermal conductivity as a diamond, high-frequency sounds are produced during the test. [Warm reminder]: Make sure to follow the correct testing procedures and avoid using diamond testers on unsuitable items (metal, skin, water, etc.) to accurate test resu