Bells are a big part of Afro-Cuban music and rumba. Traditionally it is rumba columbia that uses the bell to play what most people call the "6/8" bell. However it is not unusual to hear a bell playing clave for guaguanco. Sometimes you will even hear people play the upbeats in a guaguanco on a bell. That's not strictly traditional, but the part fits and sometimes people just have to play something.
There are several styles and sizes of bells, including the guataca, which is a hoe blade. Choosing a bell, and even more, finding a bell that you like is very subjective. Most important is the sound, but also very important is the weight. What you hit the bell with also makes a big difference. Usually the striker tends to be a drums stick, as these are so commonly available. However the guataca and the "double bells'' called agogos you see in the photo are commonly struck with a thin metal rod, or even a "8 penny" nail, or some other piece of metal.
Just like the claves, make sure you get a bell you like, and that is not too heavy. You might be hearing it and holding it for a long time.
The bell goes by different names. Most common is campana, though you hear cencerro used. Agogo is the name for the double bell, and I believe in Abakua the bell is referred to as Ekon.