7019.66 - Plain weave, weighing less than 250 g/m2, of filaments measuring per single yarn not more than 136 tex:

This HTS classification covers woven fabrics made from glass fibers, specifically those that are plain woven and weigh less than 250 grams per square meter. The individual yarns composing these fabrics must measure not more than 136 tex. The "plain weave" specification refers to a basic weave structure where each warp yarn passes alternately over and under each weft yarn, creating a simple, uniform pattern.

While the parent category addresses a broad range of glass fiber articles, including mechanically bonded fabrics, this specific node narrows the focus to woven structures with defined weight and yarn thickness parameters. The emphasis on plain weave distinguishes these fabrics from those with more complex weaves, such as twill or satin.

This category further divides based on color. The subcategories differentiate between glass fiber fabrics that are not artificially colored and those that have been dyed or otherwise colored. This distinction is crucial for customs purposes, as colored textiles can sometimes be subject to different tariff treatments or reporting requirements.