SureFire HID Torches
HID LAMPS - The Ultimate High-Output Light Source
High Intensity Discharge (HID) lamps do not use a tungsten filament, as do incandescent lamps. Instead, they use a clear quartz capsule (an 'arc tube') having electrodes at either end and containing high-pressure xenon gas and additional chemical components. When sufficient voltage is applied to the electrodes the gas inside the tube is heated and ionized, enabling it to conduct electricity in the form of an 'arc' (basically a sustained electrical spark), and causing it to emit light. When functioning, pressure inside the arc tube rises to several times atmospheric pressure.
HID lamps are both extremely bright and highly efficient - with an equal power input, they produce many times the lumen output of a tungsten incandescent lamp and their operating life far exceeds that of comparable incandescent lamps. An additional benefit: since they have no filament to break or burn out they are extremely resistant to mechanical shock and vibration.