[Fast and Safe]: The Professional Diamond Selector II indicates genuine or fake diamonds. It is designed for fast, accurate, and safe diamond testing. [Intuitive Design]: Features an LCD display and LED indicator. Uses large/small probes to test diamonds and emits audible sounds to easily differentiate readings. [Easy to Use]: The diamond tester pen is simple to operate and provides quick results—no professional experience required. Simply turn on the pen, place the tip on the gemstone with light pressure, and listen for the beep. If the stone is fake, crystal, or cubic zirconia, the tester will not beep. Note: Measurements are manually taken. Please allow 1-25 cm variation. Color differences may occur due to lighting and screen settings. Actual product may vary slightly.