This is a small prayer bell from Wat Doi Suthep in Thailand. I have several of different size around garden, hanging from the trees. They are cast bronze and each has a single,clear note.
A Buddhist monk tried to explain them to me. Through pantomime I guessed something about a prayer when the wind stirs the bell's clapper. All about the glittery temple were many sizes of bells, mostly hung by people, each bell with a private prayer. I asked a Thai man to write the names of some friends and my family on them. The writing has faded, but the bells still sing their prayers all the same.
Here's a link to Wat Doi Suthep if you want to learn more about it. (http://en.wikipedia.org/wiki/Wat_Phrathat_Doi_Suthep)