The automated COSC-Accredited PF441 chronometer movement that this Parmigiani common runs on provides a 55-hour energy reserve, owing to its oscillating mass, that is in delicately engraved gold, and may be admired through the sapphire crystal caseback. And admire it you will, as it shows many of the very best https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/