Importers should obtain certified dimensional specifications from the manufacturer for each product — specifically nominal thickness in millimeters and sheet area in square meters — and map those to the applicable 10-digit line before filing the entry. Because the lines are defined by precise numeric thresholds (e.g., not over 1.5 mm, 1.5–2 mm, 2–3.5 mm, 3.5–5 mm, over 5 mm) and area cutoffs (e.g., not over 0.26 m², 0.26–0.65 m², over 0.65 m²), even small measurement discrepancies can shift classification. A licensed customs broker with glass experience is advisable for high-volume programs.

Both countries host significant flat glass manufacturing capacity oriented toward electronics and display applications — thin drawn glass for LCD panels, cover glass, and precision optical uses — which aligns with the thinner-gauge lines prominent in this heading. Their production is often targeted at the US electronics supply chain, making origin concentration a factor importers should weigh when assessing Section 301 exposure on Chinese-origin alternatives.