No question it's my Air Zounds bike horn. It's loud enough to get the attention of distracted drivers talking on their mobiles.....a true life saver.

Not long ago on my evening commute home I was at the intersection of a highway and smaller street. There is a four way stop light. I had the green coming from the smaller street. Some knuckle head wanted to blow the red light to turn from the highway to the smaller street. I blew my horn and he VERY quickly slammed on the brakes, whacking his head on the windshield. What an idiot......