Like most modern cars, the '01-'05 Miata suffers from yellow and cracking headlight housing plastic. Polishing works temporarily, but is labor intensive and doesn't last too long. Sourcing a good used headlight that isn't also faded is difficult and expensive. New factory headlights are even more money.
These aftermarket housings offer another way. A sleek, modern housing with either a chrome or black finish. Mimicking the original headlight housing means the headlights bolt up to the vehicle just like the originals, and also offer factory plugs for both the high beam and low beam lights. If that's all that is desired, no extra wiring is necessary.
They also offer an LED Halo and LED eyebrow that can be wired in separately if so desired. These LEDs can be done either as running lights, switched separately like fog lights, or left unwired at the installer's discretion.