Noil silk is the short fiber combed out during silk processing and produces a textured, matte fabric classified under 500710 regardless of its percentage share. The 500720 subheading applies to fabrics woven from long-filament silk or other silk waste (excluding noil) where silk content is 85% or more by weight. A fabric blending noil with other fibers may fall under 500790 if it meets neither prior criterion.

Woven silk fabrics are not broadly subject to Section 301 or antidumping measures at the heading level, but duty treatment varies by subheading and country of origin. Importers should verify the specific tariff line and origin combination against current CBP and USTR guidance before entry.