This is the Portable Warning Siren. It is an Air-Raid siren you can tow somewhere and let rip. Every trailer weighs 1.1 tons. The Chrysler weighs 3 tons though. Every siren in this pack is a real siren and can be found somewhere in the world.
Sirendude2011- N/B, Sounds, and Mesh
Pfuu- fixing the N/B so it didn't crash RoR when you entered it (thank you!)
Here is how they work-