I am beginning to list a number of carved Indonesian artifacts which I bought in Bali and Java and Sumatra on a trip in the mid-1990s. They are of various materials and styles, but all are quite nicely done, in the old style if not actually antique.
This is a small medicine container, probably Batak from Sumatra. I bought it at an "antique" shop in Bukittinggi, West Sumatra. I believe it to be older, but cannot verify that information. Total height is 3.8 inches. Both the stopper and the container are carved water buffalo horn. Photo shows the detail of the carving. The two pieces fit together by pressure.