The automatic COSC-Accredited PF441 chronometer movement that this Parmigiani common operates on offers a 55-hour electrical power reserve, owing to its oscillating mass, that's in delicately engraved gold, and can be admired from the sapphire crystal caseback. And admire it you might, since it shows many of the finest decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/