[Fast and Safe]: The Professional Diamond Selector II detects real and fake diamonds. Designed for fast, accurate, and safe testing. [Intuitive Design]: LCD display, LED indicator. Uses large/small switches to test diamonds and produces audible signals for easy differentiation. [Easy to Use]: The diamond tester pen is easy to use; no professional is required to get results. Simply turn on our diamond detector pen; place the tip of the tester on the gemstone (light pressure is enough). If the stone is fake, crystal, or cubic zirconia, the tester will not beep. 1. Install the battery, turn on the power indicator light; after a while, the preheating indicator light will light up! 2. When testing, set the three-color indicator light to the fourth grid, then press the triangular iron plate on the back with your hand, and align the probe vertically with the object to be tested. If it is a diamond, the light will turn to the ninth grid or above, that is, the red light area, and makes a