HID stands for High Intensity Discharge. It refers to lighting technology that relies on an electrical charge to ignite xenon gas contained in a sealed bulb. The technology of HID automotive lamps is similar to that of common vapor-filled street lamps. HID lighting doesn't have a filament but instead creates light by igniting an arc between two electrodes via control system (ballast), 12 volts d.c. increase to 23,000 volts d.c. instantly, the xenon molecules convert to ion. HID lights get their name from the intense white light produced by the electrical discharge. HID lamps are also called xenon lamps, referring to a gas inside the lamps. HID general lighting has been used for years in sports arenas and stadiums around the country. http://www.xenonback.com