The automatic COSC-certified PF441 chronometer movement that this Parmigiani vintage operates on provides a 55-hour ability 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 may, as it displays a few of the finest decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/