The automatic COSC-Licensed PF441 chronometer motion that this Parmigiani basic runs on offers a 55-hour energy reserve, owing to its oscillating mass, that is in delicately engraved gold, and may be admired in the sapphire crystal caseback. And admire it you will, as it shows some of the best decoration https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/