Monofilaments of less than 67 decitex are treated as filament yarn and classify under headings 5402 or 5403 depending on fiber type. Monofilaments of 67 decitex or more — provided the cross-section does not exceed 1 mm — classify under 5404. The decitex weight per unit length is the primary threshold, and laboratory measurement is often needed for borderline products.

Synthetic strip under 540490 refers to flat, ribbon-like forms produced by slitting or extrusion, with a width not exceeding 5 mm, that resemble yarn in their use as a weaving element. A woven tape, by contrast, is a finished fabric construction made from such strips or yarns and would classify in the woven fabric chapters. The strip itself — before being woven — is the article covered by 540490.