Noticeable from the caseback, the oscillating mass on the motion is delicately engraved. It really is constructed from 18-karat gold and decorated by hand using a barley grain sample, completed by guilloche If the Omega has the phrases 'Master Chronometer' to the dial—as is witnessed in the Seamaster Diver 300M—you https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/