10 Dollars

Australia's polymer banknote program, developed jointly by the Reserve Bank and the Commonwealth Scientific and Industrial Research Organisation through the 1980s, made the country the first in the world to issue a complete circulating polymer series. This $10 was part of that rollout. The substrate itself — biaxially oriented polypropylene — was a genuinely novel material for currency, and Note Printing Australia eventually licensed the technology to central banks across dozens of countries.

The clear window, rather than being a separate inserted element, is an inherent feature of the unprinted polymer base — a manufacturing distinction that matters when authenticating the note against later imitations from issuers who adopted similar but technically distinct window approaches.