When it comes to picking a new set of Mercury headlights, the choices can be confusing. But whatever technology you choose, make sure that you purchase your Mercury headlights set from a recognized brand name manufacturer. Purchasing from sites that advertise no-name, cheaper headlights means that you risk purchasing headlights with much shorter lifespan, or that will not match colorwise. When the bulbs burn out on these cheaper headlights, you may find it hard to buy suitable bulb replacements with the same kind of connectors. You may have the choice of going with a halogen or HID/Xenon Mercury headlights. These new HID/Xenon headlights are much brighter than halogen lamps, as well as being more energy efficient and draw less current from the battery. HID/Xenon bulbs use a mixture of xenon gas and halide salts to create a powerful light, with a bluish tint. Halogen bulbs use a filament that creates light from basic ohmic resistance across a filament (much like your basic, old-fashioned light bulb). Halogen bulbs rely on the 12v system in the car, while HID bulbs use a ballast. The new HID/Xenon headlights are much more powerful than halogen bulbs, so make sure that your headlights are aimed correctly after installation. Turn the adjusting screws slowly (they are usually the larger screws, with springs attached) and review the beam's location frequently to avoid adjusting the headlights in the wrong direction.