Bells, horns and other noisemakers can be mounted to any bicycle, but whether or not you should put one on yours, depends on how and where you ride and how you like to warn others while riding. Some cyclists prefer to simply use their voices to caution walkers and motorists when necessary. The thinking here is that the human voice is adjustable from a whisper to a shout so you can adjust it to get the desired effect, speaking softly to joggers so you don't startle them, or torturing your tonsils screaming "stop!" to alert an asleep-at-the-wheel driver.
Bells have their advocates, though. They're inexpensive, easily mounted, don't weigh much, are simple to use and they make a friendly chime that walkers instantly recognize as a bicyclist about to pass. Which is also why dingers work well for trail use. Bell people usually ring to say hello to other bikers, too, which is a nice tradition. And, because even the loudest ding, may go unheard inside a car, if you need to make a louder warning, you can always shout.
Although there are some battery-powered and pneumatic designs intended for enthusiasts, most bicycle horns are the squeeze type usually of interest to young children (who shouldn't be riding in traffic situations) who want something mostly for fun.
Feel free to come in and make a racket trying out our selection of noisemakers to find one right for you.