The automatic COSC-certified PF441 chronometer movement that this Parmigiani classic runs on offers a fifty five-hour energy reserve, owing to its oscillating mass, that's in delicately engraved gold, and may be admired through the sapphire crystal caseback. And admire it you might, as it displays a few of the best https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/