The automatic COSC-certified PF441 chronometer movement that this Parmigiani basic operates on offers a 55-hour power reserve, owing to its oscillating mass, that's in delicately engraved gold, and can be admired in the sapphire crystal caseback. And admire it you can, as it shows a few of the very best https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/