A: Both grades provide identical thermal insulation because vacuum efficiency depends on the inter-wall spacing and copper/aluminum radiation barrier. SUS316 offers superior corrosion resistance against saline, acidic, or isotonic sports drinks, while SUS304 handles standard water and coffee requirements.

A: Every single flask passes through an automated high-precision vacuum decay testing machine on the production line. Units failing to maintain internal pressure differentials are automatically rejected.

A: Yes. Provide the Pantone C or U color reference, and physical color chips will be shipped for client approval within 4 business days before mass production begins.

A: Standard packaging includes individual white boxes or kraft boxes with protective sleeves. Custom color-printed gift boxes, cylinder tubes, and barcode/FNSKU labeling can be prepared per retail specifications.

A: Stock samples are provided free of charge (freight collect). Customized pre-production samples involving specific pantone colors or laser engraving incur a setup fee, which is refundable upon placement of the bulk order.

A: We support FOB, CIF, and DDP terms via major shipping ports. Each shipment includes commercial invoices, packing lists, Bills of Lading, Certificate of Origin (COO), and batch material test reports.