This is what designer Masayuki Kurokawa has to say about Balloon Shakers:
Traditionally, salt and pepper shakers have one hole for pepper and three holes for salt and the container is usually opaque so the contents inside can not be seen. The concept behind the Balloon Shakers was so you can see what's inside the shaker as it can be used for not only salt and pepper, but all kinds of seasonings.
I think these are pretty fantastic.
From Merchant no. 4 (I LOVE this shop, by the way.)