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