Noticeable throughout the caseback, the oscillating mass on the motion is delicately engraved. It is actually constructed from eighteen-karat gold and decorated by hand having a barley grain sample, carried out by guilloche The Diver 300M is obtainable in metal or mixtures of metal and yellow or Sedna gold, by https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/