Noticeable in the caseback, the oscillating mass of your movement is delicately engraved. It is actually produced from 18-karat gold and decorated by hand with a barley grain pattern, performed by guilloche A paragon of robustness and reliability, the 40 mm Oyster circumstance of the new GMT-Learn II is confirmed https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/