Visible in the caseback, the oscillating mass in the motion is delicately engraved. It is made out of 18-karat gold and decorated by hand which has a barley grain pattern, finished by guilloche If the Omega has the words 'Learn Chronometer' within the dial—as is found during the Seamaster Diver https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/