Non-destructive Testing This diamond tester is specially designed for true and false gemstone testing, not only fast and accurate, but also safe, used to distinguish real diamonds from other imitation stones, without adverse effects on gemstones, suitable for: masonry, crystal, agate, red Sapphire, Emerald and more, it is a great tool to test your jewelry EASE OF USE The intuitive display design of the LCD display and LED indicator light makes the operation of the diamond checker tool easy. The probe and the object to be tested must be at a 90-degree angle, and the authenticity of the gemstone can be quickly identified according to the sound and reading (such as cubic zirconium (CZ)) Such imitations will not react when detected) COMPACT SIZE FOR EASY PORTABILITY Our high accuracy diamond tester measures about 6.3 x 1.57 x 0.87 inches, it is small and portable, it is light in weight, it can be put into any handbag or backpack, and it will not put too much burden on you when using it MATCHING BATTERY Each diamond tester pen has a matching alkaline mercury-free environmentally friendly high-performance battery (DC 9V battery), so you don't need to spend extra effort to choose a matching battery NOTICE Please read the instructions carefully before using the professional diamond tester , and use this product correctly in order to test out accurate results