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