The automated COSC-certified PF441 chronometer motion that this Parmigiani common operates on offers a 55-hour electrical power reserve, owing to its oscillating mass, which happens to be in delicately engraved gold, and can be admired with the sapphire crystal caseback. And admire it you'll, mainly because it shows a lot https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/