Every single stainless steel bottle and tumbler undergoes our mandatory 100% two-step vacuum testing procedure. After the automated 10^-3 Pa high-temperature vacuum brazing furnace process, products pass through automated infrared thermal imaging scanners to verify absolute vacuum integrity. We guarantee our double-wall vacuum products maintain boiling liquids hot for 12 to 24 hours (temperature above 55°C) and ice water cold for 24 to 48 hours.

Yes. All products manufactured by Quanzhou Unifan comply with strict international food safety standards. Our stainless steel alloys (SUS304 and medical-grade SUS316) and BPA-free Tritan/PP lids are tested annually by SGS, TÜV Rheinland, and Bureau Veritas, fully complying with US FDA 21 CFR 175.300, German LFGB (§ 30 and 31), and California Proposition 65 (zero lead, cadmium, or phthalates). Full test reports and Declaration of Conformity (DoC) dossiers are provided upon request.

SUS304 (also known as 18/8 stainless steel, containing 18% chromium and 8% nickel) is the global gold standard for food-grade drinkware, offering exceptional corrosion resistance and mechanical strength. SUS316 contains an additional 2% to 3% molybdenum, which provides enhanced resistance against chloride pitting and acidic liquids such as coffee, citrus juices, electrolyte sports drinks, and tea. We offer SUS316 inner liner upgrades across all our vacuum flasks and food jars.

Yes. Our automated electrostatic powder coating lines utilize automotive-grade polymer resins cured in precision thermal ovens. Our coated bottles undergo ASTM D3359 and ISO 2409 Class 0 cross-hatch tape adhesion tests and withstand 50+ cycles in commercial dishwashers without blistering, peeling, or fading. For products featuring delicate metallic foil decals or vacuum electroplating, gentle hand washing is recommended.

Custom private mold tooling for new bottle shapes or proprietary lids requires 15 to 20 working days from final CAD sign-off. We sign legally binding Non-Disclosure Agreements (NDA) and Non-Compete agreements prior to receiving client drawings. Tooling fees can be fully amortized and refunded once aggregate order volumes reach agreed thresholds (typically 30,000 to 50,000 units). Clients retain 100% proprietary ownership of their custom molds.