This article lists the outdoor warning sirens built by Biersach & Niedermeyer Co., Alerting Communicators of America and American Signal Corporation.
9/12 (Gen 2 and 3) The T-135 AC was known as ACA P-50, the name was changed after ACA's bankruptcy.
The T-135 AC/DC is a siren that is bigger and more powerful than the T-128 and has a similar design and also has a battery backup system.
This was introduced around 2007, replacing the T-135 AC.
The T-121 is an 8 port siren that has a similar design to Federal Signal's Eclipse 8.