Large ivory ear plug would have been worn by both men and women of the Karen ethnic group of Eastern Burma and northern Thailand. Such plugs were inserted into large holes in the ear lobes.
It is carved from a single piece of ivory.
Similar examples are illustrated in Hoek (2004, p. 210) and Lewis & Lewis (1984, p. 34-35).
The example here is in fine condition. The edge of the base has an old chip (which itself has patina) and the ivory has a wonderful patina from age and handling that varies from a honeyed yellow to a nutty brown.
References
Hoek, C., et al, Ethnic Jewellery: From Africa, Asia and Pacific Islands, Pepin Press, 2004.
Lewis, P. & E., Peoples of the Golden Triangle: Six Tribes in Thailand, Thames & Hudson, 1984.