Stainless steel is unquestionably the most conventional of watchmaking resources for outer craftsmanship, and offers natural beauty, strength and affordability. It consists of the melting of the raw material working with oxyhydrogen flame and also the crystallisation with the melted droplets to type a cylinder. Graded 9 about the Mohs-hardness https://www.watchesworld.com/top-10-dive-watches/