... , Refractive Index: 1.30-1.81, Size: 30x70x130mm. Gem Refractometer CL-181LLGem Tester Refractive index is one of most important optical ... is a popular instrument used in jewelery market.Gem refractometer CL-181LLDescription: 1)Gem refractometer, glass testing table-board,black color ... may possibly not be shipped owing to air shipping limit. CL-181LL Gem refractometer