The automated COSC-Qualified PF441 chronometer movement that this Parmigiani typical runs on offers a fifty five-hour power reserve, owing to its oscillating mass, which happens to be in delicately engraved gold, and will be admired through the sapphire crystal caseback. And admire it you may, as it displays a number https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/