The Dials include sunray and guilloche finishes, and therefore are usually secured by scratch-resistant sapphire crystals. Attached for the instances are buttery-smooth Barenia leather straps, usually in the color of the choosing. The term “chronometer” took on a slightly broader meaning as personal, transportable timekeeping, as represented by pocket watches https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/