High Intensity Discharge (H.I.D.) is a type of lighting technology that replaces the filament of the light bulb with Xenon gas. The gas is ignited to produce an arc of light, when high voltage is applied. The amount of light output is three times that of a standard halogen bulb. The lamps also glow at a higher light temperature (closer to natural sunlight) that gives it its distinct color and appearance.

Other companies produce halogen bulbs that are gas-filled. They still have a filament as they are halogen technology, but the gas gives the bulb a bluer color when lit. Xenon-filled halogen bulbs produce little or no more light output than standard halogen bulbs of the same wattage.

"It should be noted that halogen technology is not comparable to the Xenon discharge technology, fitted as original equipment to more and more of the world's finest cars. " - Philips