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