25 Penny    (售价 $21.0)

1977, Tristan Da Cunha (St.Helena Dependency). Large Proof Silver 25 Pence Coin.

Mint Year: 1977
Reference: KM-1a.
Mintage: 25,000 pcs.
Condition: A nice Proof!
Denomination: 25 Pence
Material: Silver (.925)
Weight: 28.28gm
Diameter: 38mm

Tristan da Cunha (/ˌtrɪstən də ˈkuːn(j)ə/), colloquially Tristan, is a remote group of volcanic islands in the South Atlantic Ocean. It is the most remote inhabited archipelago in the world, lying approximately 2,787 kilometres (1,732 mi) from Cape Town in South Africa, 2,437 kilometres (1,514 mi) from Saint Helena, 3,949 kilometres (2,454 mi) from Mar del Plata in Argentina, South America and 4,002 kilometres (2,487 mi) from the Falkland Islands.

The territory consists of the inhabited island, Tristan da Cunha, which has a diameter of roughly 11 kilometres (6.8 mi) and an area of 98 square kilometres (38 sq mi); the wildlife reserves of Gough Island and Inaccessible Island; and the smaller, uninhabited Nightingale Islands. As of October 2018, the main island has 250 permanent inhabitants, who all carry British Overseas Territories citizenship. The other islands are uninhabited, except for the South African personnel of a weather station on Gough Island. 

Tristan da Cunha is one of three constituent parts of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha, with its own constitution. There is no airstrip on the main island; the only way of travelling in and out of Tristan is by ship, a six-day trip from South Africa.