Kina is the national currency of Papua New Guinea. The name derives from the pearl oyster that circulated as traditional money in the highlands of Papua New Guinea until the 1960s. The semilunar polished oyster shells were known as "kina" in the highlands. On the Gulf of Papua they were called "mairi." The modern kina banknotes all feature different forms of traditional currencies. The reverse of this 2 kina bill shows a stone axe from Mount Hagen, a Kula arm band from the Milne Bay Province, engraved dog teeth from the Bougainville Area and a clay pot from the region of the Sepik River.