I needed a loud horn for a pump alarm I was making. Went to the junkyard and asked for a loud one,the guy says "Oh yeah",and brings me one for $12. Don't know what it came off of, the writing on it looks like Russian. It only buzzed when I hooked it to a 12 volt power supply,but when I hooked it to a battery, ouch! you don't want to be within 50 feet of this one. Turns out that it draws 35 amps. I have it mounted on a 15 foot pole,you can hear it two miles away. So they are out there.