Obvious from the caseback, the oscillating mass on the motion is delicately engraved. It can be created from 18-karat gold and decorated by hand having a barley grain pattern, done by guilloche A paragon of robustness and trustworthiness, the forty mm Oyster scenario of the new GMT-Master II is confirmed https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/