Buyers must prioritize the base metal composition based on the application. For fashion and luggage, Zinc Alloy (Zamak 3 or 5) is preferred for its excellent casting properties and plating finish. For high-end hardware or marine use, Stainless Steel (304 or 316 grade) is essential for corrosion resistance. Always request a Material Test Report (MTR) to verify the chemical composition and ensure the absence of restricted heavy metals like Lead, Cadmium, and Nickel, especially for products entering the EU or US markets.