The automatic COSC-certified PF441 chronometer movement that this Parmigiani basic runs on offers a 55-hour electric power reserve, owing to its oscillating mass, which happens to be in delicately engraved gold, and can be admired with the sapphire crystal caseback. And admire it you may, as it displays a lot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/