The automatic COSC-certified PF441 chronometer motion that this Parmigiani typical operates on offers a 55-hour power reserve, owing to its oscillating mass, that is in delicately engraved gold, and may be admired throughout the sapphire crystal caseback. And admire it you will, since it displays many of the finest decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/