In the 1950s and 1960s several manufacturers supplied chronograph wristwatches to the French armed forces, originally designated "Type 20". One of the requirements of the French Defence Ministry was the "retour en vol" or "flyback" function, allowing to instantly stop, reset and restart the chronograph function with a single press of the lower button. The other basic mechanical specifications for the Type 20 included an accuracy to within 8 seconds per day, a power reserve of at least 35 hours and the aptitude to handle the start-stop-reset operation 300 times without any problems.
These chronographs were mainly destined for pilots and flying personnel of the French Air Force, French Navy and the CEV, Centre D'Essai en Vol, the French flight test centre, and overhauled every year. After each servicing, the backs of the cases were marked with the letters "FG" for "Fin de Garantie" or "end of guarantee" followed by the date for the next maintenance. Number 5101/54 refers to the order number and year of the contract.
Breguet's Type 20 is the most renowned and most desirable of these French military chronographs. It was produced in small quantities until it obtained the official approval of the French services in 1950. As of 1954, the French government commissioned Breguet with the supply of the Type 20 to the Air Force, the Naval Aviation Forces and the CEV.