The European Central Bank has unveiled a new version of the commonly used 20-euro note with added anti-counterfeiting features.

European Central Bank head Mario Draghi signed a large facsimile of the new note at a ceremony Tuesday at bank headquarters in Frankfurt.

The new note has a "portrait window" security feature. When the banknote is held against the light, the window becomes transparent and reveals a portrait of Europa, the mythological figure who gave her name to the continent. It follows new versions of the 5-euro and 10-euro note.

The note is being made available for testing nine months ahead of its Nov. 25 introduction so that companies can make sure testing devices used by retailers are ready.