The automated COSC-Qualified PF441 chronometer movement that this Parmigiani classic runs on offers a 55-hour electric power reserve, owing to its oscillating mass, that is in delicately engraved gold, and can be admired through the sapphire crystal caseback. And admire it you may, as it shows a few of the https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/