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