Obvious from the caseback, the oscillating mass of the motion is delicately engraved. It's made from 18-karat gold and decorated by hand by using a barley grain sample, finished by guilloche The Diver 300M is available in steel or combos of steel and yellow or Sedna gold, which has a https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/