Neck Ring „kalabubu“

The neck ring is made of coconut slices strung on a brass ring. A brass disc serves as a closure.

Nias society was once governed by a rigid hierarchical class system consisting of an aristocratic ruling class, commoners and slaves. An array of regalia was used by aristocrats and commoners to mark status, in accordance with wealth and power. Only successful headhunters were allowed to wear this ring, became full members of the male community and were sought-after marriage candidates. 

Following the prohibition of headhunting on Nias by the dutch in the early twentieth century, the accoutrements of warriors continued to be used for ceremonial performances, e.g. wedding ceremonies, and honored as ancestral heirlooms.

en. wikipedia.org:

COLLECTIE_TROPENMUSEUM_Studioportret_van_een_man_in_krijgskleding_TMnr_60046