Yes, this is a 20V1T. Its rotors are synced with each other, whereas the 16V1T-B's (having 2 independent DC motors) rotors are slightly out of sync with each other.

According to Sentry's website, the single tone version is called a 20V1T. The 16V1T-B is a single-tone unit with dual DC motors that never run at exactly the same speed, creating a slight dissonance between the rotors.

Now thatd be one sight to see and hear!

Now I see what you are talking about. I have been on the Sentry website many times and just now noticed it does say 20V1T. I have to agree with you. It indeed does sound like a 20V1T.

The reason it is labeled at 20V1T is because is a single tone version of the 20V2T. 1T = one tone and 2T = two toned.

Sentry can really make either. I've seen them make 16 port 5Vs and 20V2Ts with all skirts and no horns. I would imagine that it would still be labeled as a 20V2T, but considering how Sentry comes up with their model numbers, it would really make sense for this one to be labeled a 20V1T.

This siren isn't 10/15, it has the double-8 setup. The only siren that's able to have the 10/10, 10/15, and 15/15 port ratio is the 40V2(1)T. All other dual toned Sentry sirens are 8/16 port, and can be configured in double 8-port rotors (like this one), double 16s, or the standard 8/16. The smaller ones (3V8, 7V8, 10V) can be either 8 port or 16 port.

I saw and heard that siren or something like it in Sterling, CO. The first time was the friday noon test. Second time was a tornado warning.

I couldn't agree more but it is a 20V2T. And the correct term would be 16V1T-B

About 128 dB at 100 ft.

I like this Siren...it has that Classical look to it....Great that they still make these...i just wish more places around me would install them..the closest Sentry is about 34 Miles to my South. :-(

Charlie only the 40v2t can come with 10/15. you have it backwards.

Sounds more like a 20V1T.

ahh I see, I always thought the T meant tier... as in rows of horns. Using my logic this would be a 2T... but my logic is flawed, haha