An electronic device used for displaying numerals or other information using glow discharge developed in the 1950's. They're a glass tube filled with a low-pressure gas, such as neon, and contains a wire-mesh anode and multiple cathodes shaped like numerals or symbols. Applying power to a specific cathode surrounds it with an orange glow discharge.
The technology was superseded in the 1970's by light-emitting diodes (LEDs) and vacuum fluorescent displays (VFDs).
