brand Features: Specially designed: This refractometer is designed to measure the refractive index of gemstones and solid materials. Many people think that gem refractometers are the most important of all gem test instruments. The primary use of a refractometer is to measure the angle at which light is bent or refracted through a stone. High precision, compact and easy to carry: The refractometer is highly accurate and easy to operate. Lightweight and compact, it is easy to carry. It provides important gemstone recognition as it differs from gemstones to gemstones. The refractometer is also one of the few instruments that can provide you with information on opaque gems and transparent gems. : low battery consumption and long service life. The possible gems continue to be eliminated by values such as R.I., Color, Hardness and S.G. The transparent gemstone is tested and the surface is polished flat, which is very suitable for separating gemstones. Quick identification: Quickly and accurately identify single and double gems. Helps identify diamonds, for moissanite and colored gems, speeds up the identification of gems in the package, does not require RI liquids, and results in uniform and reliable results each for time, with a clearly visible display for easy reading measurements. Gem Refractometer Set only,other accessories demo in the picture is not included Specification: Item Type: Refractometer Refractive Index Range: 1.30-1.for 81 RI Minimum Division Value: 0.01ri Material: ABS Size: app.12.8x6x3.2cm/5.04x2.36x1.26in Color: Black Quantity: 1 Set Note: Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package Contents: 1 x Refractometer 1 x Flashlight 3 x 1.5V Button Batteries 1 x Reflecting Oil 1 x User Manual