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, comes with a convenient carrying case. Detailed user manual included in the package. The thermal conductivity meter is designed according to the thermal conductivity of diamond and is used to distinguish diamonds from imitations. Tips: Gemstones should be clean, dry, and at room temperature. During testing, place the stone 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. Designed for testing loose stones. Lightweight, comes with a convenient carrying case. Detailed user manual included in the package. Specifications: Color: Black Power supply: 1 x 9V battery (not included) Dimensions: 16 x 4 x 2.2 cm Maintenance and care: 1. The device is sensitive; handle with care and store with the probe protected when not in use. 2. Dim indicator light indicates low battery; replace promptly. 3. Remove the battery if the device is not used for an extended period. 4. For accurate results, annual calibration is recommended. Usage tips: 1. This thermal conductivity meter is designed based on the thermal properties of diamonds and is intended to help identify genuine diamonds. 2. This is a precision electronic instrument. Use in environments between 535C with relative humidity under 80%. 3. Ensure stones are clean, dry, and at room temperature before testing. 4. During testing, place the stone on the first or second grid. Package includes: 1 x Diamond Tester II