The ACA Allertor 125 is an outdoor warning siren made by Alerting Communicators of America from 1944 until 1980. It has a distinctive design with the chopper in the bottom horn and the noise coming out of the top horn.
The ACA Allertor was designed around the early 1960s as a siren with a metal horn. It had many changes throughout its production run, the most notable being the horn changed to fiberglass around 1968, then to a larger design. The Allertor was a popular choice for various communities in the Midwest from the late 60's, to the late 70's, and served as one of ACA's most popular sirens during that time. Despite being an efficient design, it was expensive to build the fiberglass horn. The Allertor was finally discontinued around 1980, and replaced with the more-efficiently designed P-10. The P-10 used a bell horn and cone intake that was much cheaper to produce.