The automatic COSC-Qualified PF441 chronometer movement that this Parmigiani traditional runs on offers a 55-hour energy reserve, owing to its oscillating mass, which is in delicately engraved gold, and might be admired from the sapphire crystal caseback. And admire it you are going to, mainly because it displays a number https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/