Visible through the caseback, the oscillating mass with the motion is delicately engraved. It's made out of 18-karat gold and decorated by hand with a barley grain pattern, finished by guilloche So If the Omega has the phrases ‘Learn Chronometer’ to the dial—as is observed Within this signature Omega Seamaster https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/