Captive flying leads with 4 mm plugs for connection to a power supply.
A metal ray box with a sliding lamp holder.
with single/double & wide/triple slit plates, and a 12 V 21 W lamp.
Takes 50 mm wide accessories.

Physics School Lab Equipment Suppliers in India 

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