It comprises a 150 x 28 mm tube, with 15 x 0.5 mm slit at one end, and 6 mm diameter aperture with 140 lines/mm diffraction grating at the other.
A simple, robust, low-cost tube spectrometer ideal  introducing the concept of spectrometry.
When a light source is observed through the device, the original and first order images can be seen.

Physics School Lab Equipment Suppliers in India 

Ltekonline are the manufacturers of Tube Spectrometer Light and Optical Lab used to demonstrate engineering principles in Engineering Colleges, Engineering Schools and Physics Lab Experiments for Engineering Teaching Lab in Universities