1997 was the first year in which Australia released two commemorative one dollar UNC coins on the same theme - the centenary of the birth of Sir Charles Kingsford Smith. 

Not only do Kingsford Smith's heroic feats inspire collectors across the generations, but this dual set includes the incredibly rare portrait type that wasn't included in the standard commemorative folders.

The only way a collector can get one for their set is to buy one of these dual sets.