The Dials incorporate sunray and guilloche finishes, and are normally secured by scratch-resistant sapphire crystals. Connected to the conditions are buttery-clean Barenia leather straps, generally in the color of the choosing. Chronographs — with their bezels, scales and sub-dials — in many cases are considered to be far too complex https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/