The Tuvaluan Dollar is the currency of Tuvalu - a small nation in the Pacific Ocean. Tuvalu has never had banknotes of its own, and has been issuing coins since 1976; these circulate together with coins of the Australian Dollar, which is also legal tender in the country, and to which the Tuvaluan Dollar is pegged.
The Australian Perth Mint issues a large variety of non-circulating legal tender coins under the authority of Tuvalu. Some of these are in the silver ounce format (abbreviated as 1 oz). Strictly speaking, they are not bullion as they are priced at a premium and are targeted at collectors who appreciate them for their artistic merit and collectable value and not just for their precious metal content.
This coin is part of a Perth Mint range featuring characters from the Transformers science fiction film series which is about alien robots.
The mint says about it:
Four million years ago on the planet Cybertron, emotional and perceptive robots with the ability to think and feel, known as "Transformers", inhabited the planet. This highly intelligent race of "robots in disguise" was divided into two opposing groups, the heroic and admirable Autobots, and the evil Decepticons. With the ability to disguise themselves by transforming into everyday vehicles such as cars and trucks, the robots can live undetected on Earth.
Optimus Prime is the leader of the Autobots, a brave and compassionate commander determined to improve the universe. | 
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