The automatic COSC-Accredited PF441 chronometer movement that this Parmigiani traditional runs on offers a fifty five-hour electricity reserve, owing to its oscillating mass, which happens to be in delicately engraved gold, and may be admired from the sapphire crystal caseback. And admire it you may, since it displays a number https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/