Visible through the caseback, the oscillating mass from the movement is delicately engraved. It really is constructed from eighteen-karat gold and decorated by hand having a barley grain pattern, carried out by guilloche When your Omega has the words 'Grasp Chronometer' around the dial—as is found during the Seamaster Diver https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/