The Air zound is great for making noise that drivers respond to, but I stopped using it on the 3rd one in 2 years. Each time the valve that allows you to inflate the bottle seemed to fail. Once I was able to fix it by replacing the bottle. My son, the mechanical engineer, and I spent a couple hours submerging them in water, unsucessfully trying to find a way to fix them. We had fun though. I currently use a 12V car horn. Drivers really pay attention to that. It is sort of fun when someone honks at me to honk back and watch the shocked reaction. It is also great as you approach an intersection and just aren't sure that car is slowing down for it's stop sign. I also use hand held fog horns from REI. I took about a 8 inch strip of old inner tube, cut 2 holes in it that would snugly fit around the air cartridge of the fog horn. Then you slip the cartridge thru one of the holes, hold it to the handlebar, wrap the inner tube around the bar a time or 2 & finally stick the bottom of the fog horn into the 2nd hole in the innertube. It is as loud as the air zound, and has lasted longer, works better in cold weather, and is more easily moved from bike to bike. Oh, did I mention that if you want advice on how to make your bike ugly, I'm the one to talk to?