The heading splits first by surface treatment — sheets with an absorbent, reflecting, or non-reflecting layer (7004201000) versus those that are body-tinted, opacified, or flashed without such a layer — and then by sheet dimensions (thickness and area) for the latter group. Importers should obtain manufacturer specifications confirming the treatment type, glass thickness in millimeters, and sheet area in square meters to assign the correct 10-digit line.

Both flashed and body-tinted drawn glass fall within heading 700420, but they serve different markets: body-tinted glass (colorant throughout the melt) is used in solar-control architectural glazing, while flashed glass (a thin colored layer fused to a clear base) is the traditional material for stained-glass windows and decorative art. The distinction affects the applicable 10-digit subheading, so the production method should be confirmed with the manufacturer.