Determine Prism Angle Refractive Index Wavelength & Frequency measurement of Reflected light Heavy Metal base for stability Adjustable Prism table marked with grooved lines Main graduated scale of 150mm (6") Double ending verniers reading to 1 min to 30 Secs Arc depending on model Telescope mounted on movable pillar having fine adjustment Collarimeter mounted on fixed pillar with objective Eyepiece & Rack Pinion Fine Focusing