The automatic COSC-Qualified PF441 chronometer movement that this Parmigiani classic runs on offers a 55-hour electric power reserve, owing to its oscillating mass, which is in delicately engraved gold, and might be admired through the sapphire crystal caseback. And admire it you are going to, because it displays a lot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/