Sirens for emergency vehicles
Data on the siren:

Measures:  22 X 22 X 8mm

Power: max 5v
If greater voltage are neded it can be
arranged with a power regulator.

Speaker power:  1/4Watt
Speaker power depends on size of  the
speaker and type of the installation.

Filetype: Mp3 are installed through USB
Siren are very easy to handle and work with.
I can offer you a number of different sounds. But you are fee to find some yourself
If you are able to work with sounds on a computer you are free to install just the sounds you like. 
File must be in Mp3 format.  The module can be seen as an extra hard drive on your computer.
Next step are just a matter of copying the file to the module and the siren are ready.
PRICE: Siren with control unit for RC use.................................................... 95€

               Siren with control unit for static display...........................................70€