20 ATM Waterproof Automatic Dive Watch Retro CuSn8 Bronze Diver Watch

CuSn8 Bronze

CuSn8 Bronze is a common type of bronze alloy. Its name shows its main components: Cu stands for copper (the primary metal), and Sn8 means it contains about 8% tin (the key alloying element). The rest is mostly copper, with small amounts of other trace elements sometimes added. It has useful properties like good strength, wear resistance, and corrosion resistance, so it’s often used to make parts such as bearings, gears, valves, and some mechanical components that need to work reliably under friction or mild corrosion conditions.

Sapphire crystal

Sapphire crystal is a synthetic material widely used in watchmaking, created by crystallizing aluminum oxide (Al₂O₃) at extremely high temperatures (over 2,000°C). Despite sharing the name with natural sapphire, it is lab-grown and typically colorless (natural sapphires get their color from trace elements like chromium or iron). Its structure is highly dense and uniform, giving it exceptional durability and clarity—two key reasons it's a top choice for watch faces and case backs.