The small metal boxes (in a variety
of colors like brown, black, red, and white) found attached to the walls
of public buildings all over the United States are called Knox Boxes (
though manufactured by different companies, the Knox company produces the bulk
of them) and are designed to give emergency responders access to building keys (or functions like disabling power or gas lines, or turning off sprinkler systems in case
of a
false alarm) to aid in rapid entry in the event
of an emergency.