[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 beeps for easy differentiation. [Easy to Use]: The diamond tester pen is easy to operate; 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 sufficient). 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 turn on! 2. When testing, adjust 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 go to the ninth grid or higher, i.e., the red light area, and make a dripping sound. 3. If you test jade, the light will turn on at the fifth or sixth grid, indicating that the jade has reached its hardness, and no sound will be heard.