Atago India Instruments Pvt. Ltd. Manufactures Multi-Wavelength Abbe Refractometer. Atago India Instruments Pvt. Ltd. Is an ISO 9001 certified company. The Multi-Wavelength Abbe Refractometer is used to measure refractive index or Abbe number at different wavelengths ranging from 450 to 1,100nm. This Refractometer digitally displays measurement result of refractive index or Abbe number on the LCD. Measurement can be achieved by matching the boundary line with the intersection point of the cross hairs.