One of the options on the 2019 McLaren 720S Spider is the control of cabin light.
A glazed, electrochromic panoramic roof panel is available for $9,100. At the touch of a button, the tint of the roof glass can increase from 30 to 95 percent.
The glass contains a film that conducts a low voltage of electricity. As current passes through the film, particles align or disperse, allowing more or less light in.
McLaren says that when the panel is at 95 percent tint, it cuts out all but 0.1 percent of ultraviolet light. When the vehicle is locked and the retractable roof is up, the panel automatically goes to the higher tint to prevent passers-by from seeing what's in the vehicle.
But it has an additional function, said Ian Digman, McLaren's head of product management.
If the vehicle is locked and parked outside, the higher tint will keep the interior cooler, Digman said.
The 720S Spider is the latest McLaren in production to have the electrochromic panel, following the addition of the option in the 570GT last year.
The automaker has also shown electrochromic technology on the upcoming Speedtail hypercar. It can be found on portions of the doors' windows and at the top windscreen, which replaces sun visors, McLaren says.