Over the years, a bunch of vertical mystery sirens have been found in California - primarily in the cities of Sacramento, San Jose, and San Diego. For the longest time it was assumed they were made by a myriad of firms including Decot Engineering Works, H.O.R. Company Inc., and Federal Enterprises. At long last, the mystery is revealed. Information was hard to find as this was a fairly short-lived brand without much surviving material.
These sirens were actually called the Scream-Master and were manufactured in La Verne, California under this brand during the 1950s. They were simple vertical sirens, not unlike the Federal Enterprises Model 5. A louvered shroud protected the siren's chopper and motor from weather. The siren was then mounted on a pole shaped tower, supplied by Scream-Master themselves, with a maintenance basket usually stuck on the side to make periodic maintenance easier. Finally, the control boxes were signed "Scream-Master".
Many of these Scream-Master sirens were installed across California. They saw good sales in the early years and were praised for their simple but effective sirens. Unfortunately Scream-Master did not find much success out of California despite this strong beginning. They were another small company that couldn't keep up with the growing Federal Sign & Signal emporium - there is no reference to Scream-Master beyond the 1950s.
One of these sirens is supposed to be on display at the Wende Museum in Culver City, CA.
Here are a mass of photos, largely sourced from Google although I'm open to replacing these with more detailed photographs. I just found out about the Scream-Master brand this morning. Also attached is a scarce news headline detailing the Scream-Master's early success. I am open to any more material regarding this company and its sirens.