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