Neon lights are brightly emitting, electrically charged glass tubes or bulbs filled with thin neon gas or other rare gases, and are a type of cold cathode gas discharge lamp. A neon light tube is a sealed glass tube with electrodes at both ends, which is filled with some low-pressure gas. A voltage of several thousand volts is applied to the electrode, and the gas in the ionization tube emits light. The color of light depends on the gas in the tube.