Clydesdale Bank has three series of banknotes in circulation at present. The most recent set of notes, the "Polymer" Series started coming into circulation in March 2015, when the Clydesdale Bank became the first bank in Great Britain to issue polymer banknotes. The £5 commemorative notes, issued to mark the 125th anniversary of the construction of the Forth Bridge, contain several new security features including a reflective graphic printed over a transparent "window" in the banknote. Further notes in the polymer series will be introduced over time, replacing the previous paper notes.