The automatic COSC-Accredited PF441 chronometer movement that this Parmigiani common runs on provides a 55-hour power reserve, owing to its oscillating mass, that's in delicately engraved gold, and can be admired through the sapphire crystal caseback. And admire it you might, as it displays a number of the greatest decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/