The automated COSC-Accredited PF441 chronometer motion that this Parmigiani classic operates on provides a 55-hour electricity reserve, owing to its oscillating mass, which is in delicately engraved gold, and may be admired through the sapphire crystal caseback. And admire it you will, because it shows some of the best decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/