The automatic COSC-Qualified PF441 chronometer movement that this Parmigiani typical operates on provides a 55-hour electricity reserve, owing to its oscillating mass, that's in delicately engraved gold, and can be admired throughout the sapphire crystal caseback. And admire it you will, because it shows a lot of the finest decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/