Silver as a case material is quite rare, and when it is used in watchmaking, it’s typically what’s referred to as “fine silver,” or 99.9% silver. Sterling silver rings in at 92.5% silver, and the remainder is another metal like copper or nickel. It’s important to note, however, that sterling silver was commonly used in jewelry and even silverware in the early 1900s, so thematically, it’s the perfect choice for a watch that’s meant to evoke the era of Louis Blériot, who famously flew across the English Channel for the first time ever in 1909 with a Zenith watch strapped to his wrist.