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