Based off of the lightbar being used, That would be a Hänsch siren. The thing about most German Emergency vehicles, is that the lights and the sirens are one integrated system. Thing Fed Sig Vision, but with the speakers built into the lightbar. That said, you can but the siren separately, but it costs a lot. Also, you need two speakers to run it. Whelen does make a few sirens with the Martin Horn tone, but they suck. It's way too fast, and doesn't duplicate the tremelo properly. If you have room, I'd suggest getting in touch with Dr. Dennis Stouffer on the board. He's a dealer for Fiamm. They make 2 and 4 trumpet airhorn systems like the actual Martin Horns.