The automated COSC-certified PF441 chronometer motion that this Parmigiani classic runs on provides a fifty five-hour electric power reserve, owing to its oscillating mass, and that is in delicately engraved gold, and will be admired through the sapphire crystal caseback. And admire it you will, as it shows a lot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/