A 1952 advert from Federal Enterprises advertising their Thunderbolt 1000 and Model 2 outdoor warning sirens. The Model 2 is still in production today, while the Thunderbolt was made until 1990. Both can still be found in service across the North America, though many Thunderbolts are starting to be replaced with newer sirens.
Federal Enterprises now runs as Federal Signal Corporation, and many of the listed cities still use old and new Federal sirens.
