The Siren Board

I've been looking into the history of the Vietnam War, and have found that the United States bombed Laos many times, so I looked into warning sirens but found none for the time in Laos. I did find one for Vietnam though. (https://www.youtube.com/watch?v=Lv5ngh3zzrs) For Laos though, I found an article stating they will be installing electric speakers to warn the public in some places. (https://www.undp.org/laopdr/news/spread ... one-behind) From that article, and an image was found. (Shown Below.) I believe there could be some mechanical sirens in Laos, but there is no evidence of it. If anyone knows anything, help is appreciated a lot. Thanks, Even if you can't contribute. -Sentry88