The automatic COSC-Accredited PF441 chronometer motion that this Parmigiani vintage runs on provides a 55-hour electricity reserve, owing to its oscillating mass, which can be in delicately engraved gold, and might be admired from the sapphire crystal caseback. And admire it you are going to, as it displays a number https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/