ACA Penetrator-50

An ACA P-50 courtesy airraidsirens.com.

The ACA Penetrator-50 (or T-135 AC) is one of the largest and loudest civil defense sirens in the world. 

History 

The P-50 was introduced in the 1980's until 1992; at that time it was largest siren in the world. It is still one of the loudest sirens in the world; at 135 db. The vent that houses the chopper is large enough for an average sized man to stand inside. It is a dual toned siren with 8/12 ports. The New T-135 replaced it and is more efficient for it has battery backup as the ACA was not. The Cyclone was the same thing as the P-50 but it was the non rotating version. The P-50 is almost 1 ton! What does ACA stand for?? ACA stands for Alerting Communicators of America