XL Denali trims feature projector beam high-intensity discharge headlamps and light-emitting diode daytime running lamps. Sedans got quad headlamps and a new grille. Vehicles typically include headlamps and tail lights. All models equipped with Xenon headlamps were changed to projector headlamps instead. The Ford Model T used carbide lamps for headlamps and oil lamps for tail lamps. The grille was redesigned for 1991 but kept the large rectangular headlamps and crossbar appearance. This involved smoothing the edges of the headlamps and grille, and sloping the front outwards. The new model introduced larger wraparound tail lamps, dual rectangular headlamps, and squared-off body lines. Light sources for vehicle lamps other than headlamps are not Federally regulated. The first xenon headlamps contained mercury; newer types do not. This includes all HID headlamps and some high-power halogen units. It featured fender flares, hidden headlamps, and the turbo engine standard. The Sting Ray featured hidden headlamps, non-functional hood vents, and an independent rear suspension. Early prototypes included rectangular headlamps and wide tail-lamp assemblies. Amber marker lenses aligned with the headlamps wrapped around the fender sides.