Size : 39 mm or 1,5 inch. 

These WW1 "charity day" fundraising souvenirs (cardboard insignia, thin stamped medals, pin badges, more rarely bronze or silver medals) were sold during the Great War to raise money for a variety of causes : mainly supporting the troops fighting on the various fronts, supporting the war effort, supporting wounded soldiers (or having caught tuberculosis), soldier's widows, orphans, thanking allied countries, etc...