Seen from the caseback, the oscillating mass of the movement is delicately engraved. It is actually made from 18-karat gold and decorated by hand using a barley grain pattern, carried out by guilloche A gold version contains a black dial and black leather strap, and an 18-karat gold pin-buckle All https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/