Designer: obverse: Ian Rank-Broadley; reverse: Stuart Devlin
Reference: KM# 403
Diameter: 28.5 mm
Reverse A platypus and the numeral 20 are depicted against a background of water ripples. To the left of the aquatic mammal are the designer's initials 'SD' for Stuart Devlin.
Obverse The central part features a right-facing profile of Queen Elizabeth II of Great Britain wearing a crown. On the left, following the curve of the coin's edge, is the monarch's name 'ELIZABETH II'. On the right are the country name 'AUSTRALIA' and the year of issue '2007'. Below the truncation of the monarch's neck is the sculptor's initials 'IRB' for Ian Rank-Broadley.