HID Flashlight.
Another less common type of flashlight uses a High Intensity Discharge (HID) lamp as the light source. HID lamps work by discharging an electric current between two electrodes in a capsule filled with a mixture of metal halide salts and argon, producing an extremely bright light.
Some advantages of this design are that they produce more light than an incandescent flashlight using the same amount of electricity, and the lamp will last longer and is more shock resistant than a regular incandescent bulb, as they lack the relatively fragile electrical filament found in incandescent bulbs. However; they are much more expensive (due to the need for a ballast and other circuitry to start and operate the lamp) and are usually rather bulky. An example of an HID flashlight is the Surefire Hellfire Weaponlight.