1. Multi-gem Tester: This Diamond Selector II Tester is not only a diamond tester, but also a multi gemstone tester. It can detect if a gemstone is real or fake, including: diamond, sapphire, ruby, crystal, agate, jadeite, and other precious stone of various sizes.---------------2. Easy to Use: Diamond indicator will be showed if the stone is a REAL diamond (Green light).If a gemstone is fake crystal, a simulant such as cubic zirconium ( CZ ), will be no reaction.--------------3. Professional Tester: Specially developed and manufactured for the thermal conductivity of diamond, this detector is an electronic precision instrument. The operating environment is 5-35 degrees Celsius. The test stone must be clean, dry and at room temperature.-------------4. Notice: No matter what gemstone you are testing, the probe needle and the tested object must be at a 90° angle. When testing diamond, your right index finger must keep touching the metal panel on the back of the tester, while you do not touch the panel if you test other gemstones. Do Not test any metal. Do Not wear glove.---------------5. Package Contents: 1 x Diamond Selector II Tester, 1 x Texting Platform, 1 x Protected Leather Bag, Powered by DC 9V battery x 1 (Not Included).