The Cal. 6497 family is a Lépine pocket watch calibre and thus has the sub seconds dial at 9 00, in line with the crown and winding stem, but is closely related to Cal. 6498, the hunter version. It is a large movement, measuring 16.5 ligne (36.6 mm) in diameter but is only 4.5 mm thick thanks to a compact manual winding design. Modern 6497's are fully jeweled (17 jewels) though some have only 15. Most 6497's operate at 18,000 A/h, though some '6497-2 versions, like Panerai's “OP” movements, tick at 21,600 A/h. Power reserve for modern versions is 46 hours, though Panerai boasts 56 hours.
Cal. 6503 is identical to Cal. 6497 but adds a date wheel. It is 5.0 mm thick but otherwise shares the same specifications. Cal. 6503 was not updated to “-1” or “-2” specs and is no longer manufactured.
Although developed for pocket watches and far too large for the small wrist watches that were popular in the 1950's, the advent of large sports watches has made Cal. 6497 popular on the wrist. In particular, Panerai brought the movement to popular acclaim with their Radiomir, Luminor, and Luminor Marina models. Other makers who use this calibre include Alpina, Anonimo, Chronoswiss, Dornblüth, Eberhard, Guinand, Omega, Maurice Lacroix, Rado, Tissot, and U-Boat.
Cal. 6497 is also the most-widely used teaching movement in watchmaking schools, making it very well-understood by watchmakers.