The tube has a clear separation between the two electrodes and an orange glow indicates negative polarity.
A large neon-filled gas discharge tube for demonstrating electric charge and polarity.
Diameter : 13 mm
Length : 100 mm
Ignition voltage: 90 V

Physics School Lab Equipment Suppliers in India 

Ltekonline are the manufacturers of Zinc Plate with 4mm Plug for Electroscope Electrostatic Lab used to demonstrate engineering principles in Engineering Colleges, Engineering Schools and Physics Lab Experiments for Engineering Teaching Lab in Universities