From November, 1916, onwards, French pilots were issued metal wings or brevets, each of which was prefaced with an elaborate, capital “B” followed by a serial number which was hand-struck and quite small, measuring only to about 2.0 mm in height.  A total of about 15,000 of these brevets were issued during the war, after which the “B” prefix was dropped and the serial numbers doubled in height to about 4 mm.