These designs were a “bulb within a bulb”—the halogen filament itself was fully and separately encapsulated within its own glass envelope, which was then protected within the headlamp housing....

These designs were a “bulb within a bulb”—the halogen filament itself was fully and separately encapsulated within its own glass envelope, which was then protected within the headlamp housing. However, these designs did not meet U.S. standards, though they were considered more stylish and, with fuel economy becoming an issue, more aerodynamic. European vehicles sold in the United States required to comply with DOT standards had their designs modified to incorporate the U.S. sealed-beam units—often to the detriment of the vehicle appearance.