On the search for a decent horn for my velo I ran across a "loud" horn by none other than
http://loudbicycle.com/ It was a kickstarter which I funded last year; it took them over a year to deliver but it arrived last week.
The milan didn't come with a horn, and the mango's horn might as well be labeled "Fischer price" as it sounds like a toy car horn and is about as loud. A lot of people have adapted airzounds with remote relays but those have been problematic
For the record at point blank range to my cheap chinese sound meter the Airzound is 124db and the Loud is 122db and the loud sounds a lot more like a car horn than a stadium blaster.
Here's pics
http://imgur.com/a/JhkkI