Clearly different texture of the paper, yellower and more glossy.
The paper was plasticized as part of trials/tests to improve the durability of banknotes in circulation.
Quoting from Czeslaw Miłczak's catalog, we read ".... Known trial printings of HM series banknotes on plasticized paper in yellow-cream starting with the numbers 9702.... and light cream starting with the digits 9802.... or 9803... ".
Piece in issue condition. Beautiful and rare.
