The automatic COSC-certified PF441 chronometer motion that this Parmigiani vintage operates on offers a 55-hour electric power reserve, owing to its oscillating mass, that is in delicately engraved gold, and may be admired through the sapphire crystal caseback. And admire it you'll, because it displays a few of the best https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/