The automatic COSC-Accredited PF441 chronometer motion that this Parmigiani classic runs on offers a 55-hour electric power reserve, owing to its oscillating mass, which is in delicately engraved gold, and may be admired throughout the sapphire crystal caseback. And admire it you'll, as it displays some of the finest decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/