This watch was used by Paratroopers. They needed a watch which could resist to abrupt landings. In England this problem was therefore carefully studied and was resolved. They used a stock of well-constructed Longin g s movement Cal. 1268 N fitting it in an oversized and strong case the glass being fixed from the inside. Engraved on the back: "2085 - C.O.S.D. - 2340" and the "Broad Arrow". COSD means Company Ordinance Supply Depot and the number 2340 is the serial number of parat r oopers.