Visible throughout the caseback, the oscillating mass with the motion is delicately engraved. It's created from 18-karat gold and decorated by hand which has a barley grain pattern, carried out by guilloche The Diver 300M is available in steel or mixtures of steel and yellow or Sedna gold, using a https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/