With the "Firefighters in action" page you can see though, that one is on the way to a use, is often not recognized and often not well understood due to the small size.
Nevertheless, a helpful sign to, for example at the police lock over to go to the work site or to be granted on slower roads right of way.
For me personally know many in my own place, and vehicle plate and make the place more often if I sign hanging with the lettering in the disc.
The purchase is definitely worthwhile!