[MEASURE REFRACTIVE INDEX] Specially designed for accurately measuring the refractive index of gemstones and solid materials. [PORTABLE AND LIGHTWEIGHT] Easy to carry around, perfect for on-the-go identification. [HIGH ACCURACY OPERATION] Features high accuracy and simple operation for precise gem identification. [QUICK GEM IDENTIFICATION] Identify single and double gems quickly and precisely. [LONG BATTERY LIFE] Low battery consumption for extended service time. high accuracy and easy operation. Identify single and double gems quickly and precisely. Low battery consumption for long service time. Approved by strict quality and safety standards for a long and trouble-free using Colour:Black Material:plastic Package Contents: 1 x Refractometer 1 x Electric Torch (Powered by 1 x AA battery which is NOT included) 1 x 3 ML Reflective Index Fluid Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.