These LEGO key chains are based on the Atlantis them which was introduced in 2010 whose story line is about a group of explorers that are searching the sea floor for the eponymous lost city of Atlantis from ancient myths.
Summary
Gear Key Chains / Atlantis Hammer Head Key Chain set 853085 was released on March 5, 2011, retailing for $5, it has since been retired. New, unopened sets are valued at $8, while used sets sell around $7.
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