I've heard this particular size go by a couple of names. Cachimbo is one, okonkolo like the bata drum is another, and I've even heard it mentioned as an "uno" (one), I assume because it's the smallest, or first shekere somehow?
Cachimbo and okonkolo are obvious names as a 3 shekere agbe (or agwe) set plays guiro. From what I understand a guiro is similar to a bembe with drums and a toque with bata; the guiro uses primarily shekeres. From what I have seen and heard the songs for the orishas are sung at each. Just to be clear, I'm not a santero, though I know several. I enjoy the music and I enjoy educating myself on it's backgrounds and traditions.
So this little guy is done and now onto the other two. It's always a pleasure to finish one of these instruments as one is never quite sure how it is going to come together in the end; the sound, the action the appearance.