According to the archives of Montres Breguet in Paris, the present watch is possibly a unique piece. It was manufactured with red and blue enamel five minute divisions in 1931 and sold on 20 May 1952 "à Monsieur X", name of the client and amount unknown.
It is fitted with a very unusual "Chronoscope" or "Wandering Hour" dial, featuring an aperture for the hours to the head of the arrow-shaped pointer on the revolving disc. The outer chapter ring is calibrated to 60 minutes with red and blue enamel triangles for the five minutes and small silvered dots for the 4ths of a minute. The hour indication in the window changes after passing the blue enamel triangle at 12 o'clock.
The "wandering hour" dial first appeared in the 17th century. In the 1920s and 1930s Breguet sold wandering hour watches with a system patented by the Swiss watchmaker Robert Cart around 1925.
The expression "Chronoscope" is taken from the Greek "chronos" for time and "scope" for range, sector and stands for an instrument for accurate measurements of small intervals of time.