The automatic COSC-Qualified PF441 chronometer movement that this Parmigiani typical runs on provides a 55-hour electric power reserve, owing to its oscillating mass, that's in delicately engraved gold, and can be admired from the sapphire crystal caseback. And admire it you are going to, mainly because it shows some of https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/