Part 2 of this standard specifies methods for determining the fineness, thickness, corrosion resistance and adhesion of gold alloy coverings for watch cases and Accessories. Gold alloy coverings are important materials in the manufacture of watches and clocks and require excellent physical performance and durability. The standard details how to evaluate the mass of gold alloy coverings through precise testing methods to ensure their long-term Appearance and functionality during use. Test items include purity (fineness) of gold alloys, thickness of coverings, corrosion resistance and adhesion, etc., for quality control and material selection of watches and their Accessories.