Note; some versions do not feature small seconds.
A power reserve of eight days and hand-wound: the P.5000 calibre combines these two characteristics which are part of the history of Panerai watches since the first models created for the commandos of the Italian Navy. With a diameter of 15¾ lignes (35.7 mm) and a thickness of 4.5 mm, the P.5000 calibre has 21 jewels, it is made up of 127 component parts and its balance wheel oscillates at a frequency of 3 Hz, equivalent to 21,600 vibrations/hour. Its original, very strong structure recalls that of old movements in which the mechanism was contained between two plates concealing most of the wheels and allowing only a few details to be seen, such as the balance cock and the intermediate wheel.
The P.5000 calibre has a variable inertia balance, its period of oscillation being adjusted by turning the little timing screws on the outside of the balance wheel. Using this system the balance spring is free, without the curb pins which would otherwise be used to modify its active length. The bridge supporting the balance is fixed by two screws beneath which are threaded rings which turn in both directions, the purpose of which is to adjust the endshake of the balance staff pivots. This technical solution helps the escapement to continue running perfectly in the event of shocks.
The long power reserve of 192 hours, that is 8 days, is achieved by coupling the two spring barrels with toothed rims in series. The twin assembly enables longer, thinner springs to be used, resulting in a longer duration and greater uniformity in delivering energy to the movement.