★Hard CZ measuring prism.
★Scale range:1.30-1.81.Accuracy: ≦±0.002
★Professional optical design, Aluminum alloy table and Internally installed the monochromatic light.
★There are two ways of inputing the voltage:2xLR44 batteries
★3ml refringent oil(1.78±0.005)
★It is much safer ,much ecnomical and more convinent.