We discovered this sweet little bell by Gazelle when road-testing that company's bakfiets cargo bike, and we couldn't resist getting a few to offer here--all the more so as we've not yet found them for sale without a bike attached!
It's a twist-grip bell that slips onto your city bike's handlebar between grip and brake lever. Always right at hand, and thoroughly intuitive, as you need barely move your hand to ring it--and it rings when turned in either direction. Here's a recording we made of it--doesn't quite do it justice, but you'll get the idea:
A friendly way to make your presence known!
Doesn't fit all handlebars; please see details below.
All black, visually unobtrusive.
Only $12.50
If you don't run brake levers, the bell will slide up to where the handlebar curves, no matter how slightly, and stay there once you bring the grip up behind it.
If you need to remove a rubber grip, gently pry it up with a screwdriver, pencil, or chopstick and pour some rubbing alcohol down it; you should then be able to twist loose the grip with not too much effort. Alcohol also helps in reinstallation. (No, we mean on the handlebar, not in a glass! Then again....)