LED light and audio result indication. Red light will be displayed and audio indicator sounds if the stone is a real diamond. Simple calibration for stones of different sizes. Accurate and reliable reading. Lightweight, matched with a convenient carrying case. Detailed user manual included in the package. The thermal conductivity meter is designed and manufactured according to the thermal conductivity of diamond. It is specially used to identify real and fake diamonds. Tips: Gemstones should be clean, dry, and at room temperature. During the test, place on the first or second grid. V2 Gold Test Kit with Gemstone Pen, Handheld Electronic Diamond Tester with LED for Diamonds, Sapphires, Rubies, Crystal, Agate, Jade, Gems, Hardness Testing Tool Features: Easy to use. LED light and audio result indication. Red light displays and audio indicator sounds if the stone is a real diamond. Simple calibration for stones of different sizes. Precise and reliable reading. Corresponds to a test platform for loose stones. Lightweight, matched with a convenient carrying case. A detailed user manual is included in the package. Color: black. Power supply: 1 DC 9 V battery (not included). Dimensions: 16 x 4 x 2.2 cm. Maintenance and repair: 1. The instrument is very sensitive to the probe; care should be taken to protect it. When not in use, place it in the sheath. 2. If the indicator light appears very dim, the battery is low and should be replaced promptly. 3. If the instrument is not used for an extended period, remove the battery. 4. For accurate detection, annual calibration is recommended. Additional information: 1. The thermal conductivity meter is designed based on the thermal conductivity properties of diamond and is specifically used for distinguishing genuine and synthetic diamonds. 2. This device is a precision electronic instrument intended for use in environments between 5–35 degrees Celsius with relative humidity under 80%. 3. Stones must be clean, dry, and at room temperature before testing. 4. During testing, place the stone on the first or second grid. Package includes: 1 Diamond Selector II