gem refractometer, refractometers, Refractive Index: 1.30-1.81, Size: 30x70x130mm. Gem Refractometer CL-181LLGem Tester Refractive index is one of most important optical parameter. Gloss of ... light, 2ml RI liquid,manual; one year warrantyMeasuring rangeRefractive Index: 1.30-1.81Resolution Factor:Refractive Index: 0.01Size:30×70×130mmNote: 2ml RI liquid ...