1LCD AND LED DESIGN: Portable jewelry tester, with LCD display and LED indicator, to quickly identify the detected objects, has high sensitivity and high accuracy. 2HIGH EFFICIENCY: Mainly used to quickly identify diamonds and other jewelry, the measurement results are accurate, and easy to read, efficient and convenient. 3SOUND ALARM: If a real diamond is detected, the green LED will light up, and if it is a moissanite or simulated diamond, the red LED will light up and give an alarm. 4COMPACT SIZE: With compact design, this jewelry detector pen is easy to carry and store, and comes with a stone holder for easy detecting operations. 5WIDE APPLICATION: This jewelry testing pen kit is perfect for jewelry stores, auction venues and laboratories, etc., which has a wide range of applications.