What Is This Thing?

Do you know what this object does?

It's a musical telephone rest. Rain Noe of Core 77 tells us that in the 1960s and 70s, a Japanese firm named Sankyo made wind-up music boxes that turned on when the user placed a phone receiver on them. This music presumably amused or distracted the caller while waiting to continue the conversation. So think of it as a mechanical form of hold music.

Photo: Gumtree