It's a Sterling 5VX.

Heath was so ahead of his time with his sirens, the rotors are like an STH-10's but 40 years before the STH-10 existed. And this had two of them!

That's a C2 1/2, C1s don't have an eyebolt.

Airhorns such as the Diaphone use a vibrating diaphragm that's actuated by compressed air moving through it. It's quite similar to how our voices work, air moving through a diaphragm to create vibrations which result in audible sound.

Looks like the period at the end wasn't being added to it, I'll fix the link. It should work now.

Heath was very successful in California, there are far more than just 2 sirens built by the company. The Heaths you're seeing are mostly the Type K, which doesn't really have a specific design and each Type K looks slightly different from one another. There's an article on the CDS Wiki about Heath i...

There's some kind of Sterling Denver like siren in Fitzhugh Oklahoma. 34.6669472,-96.7765621 Great find! That's a Sterling Duplex, and now the 4th known Duplex that's still in existence. It was right under our noses the whole time! Again I'm sorry for the bump, but is this the same as that one? htt...

There's a few ways to tell a pre-1928 from a post-1928, mainly if you look behind the stators. The post-1928 has a large ring behind the stator where the motor cover bolts to, pre-1928s lack this. Post-1928s also have the louvred vents on the intakes, most pre-1928s do not. Some pre-1928s do have ve...

Bumping is generally frowned upon on forums. Think about how long a year is, then think of how long 5 or even 10 years is. Reviving an ancient thread whose users may not even still be around on the board is a bit pointless. This is an excusable bump however, because the link is dead so it makes sens...

Another member here who's knowledgeable about the old Sterlings says the number at the end of the name indicates the year of manufacture, not a specific model. An M45 is a Model M built in 1945, for example. Yes, that applies for units built between 1945 and 1958. Anything before and after is just ...