Unbleached Uncoated Kraft Paper & Paperboard, 225 g/m² or Over

The most frequent issue is basis weight measurement methodology: g/m² values can vary slightly depending on moisture content at the time of testing. Importers should request certified dry-basis grammage from the mill, as CBP may test samples at entry. Paperboard testing at or near 225 g/m² is at risk of falling into the 150–225 g/m² heading (480441) if the certified weight does not clearly meet the threshold.

The 225 g/m² and above range is typically used where structural rigidity and puncture resistance are critical — heavy multiwall sack inner plies, industrial protective wrapping for metal or glass, and certain construction wrap applications. These end uses require the higher caliper and stiffness that lighter grades cannot provide, making the weight threshold commercially meaningful beyond its classification function.