Why does the FRS have the little red inverted triangle at the bottom on the rear bumper?

The BRZ/FR-S is equipped with a rear fog light in countries where cars are required to have one (like those in Europe) and the US versions will get a non-functioning reflector in its place. The light is located in the red upside-down triangle on the rear bumper between the reverse lights:

US Reflector Version:



European Fog Light Version: