This is coin set is a variation of the regular Australian proof coin set for the year. It contains all the regular circulating denominations from $2 down to 5 cents, including the definitive $1 of the "Mob of Roos" type (the "regular" set contains an Armistice commemorative dollar instead).
The set is intended as a gift related to a "milestone" or a "celebration" in someone's life, and comes in a variety of cardboard sleeves marked as "Anniversary", "Happy Birthday", or a generic "Congratulations". There is an oblong metal plate that can be engraved with a personalised message.
The Mint says about it:
This new six-coin set embraces the special power of coins to celebrate many of life’s milestones. Containing Australia’s six circulating coin designs, an engravable plate, it will be an elegant and sentimental gift for anybody seeking that special something for a loved one.
Throughout history, and across many cultures, coins have been given as gifts to mark special occasions or to celebrate milestones. They have featured on such occasions as the red envelopes of coins given to Chinese children during lunar celebrations, the Hindu tradition of coin gifts during Diwali, and on wedding days. Throughout the centuries, they have become symbols of hope, wealth, prosperity and good fortune. | 
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