6105.20 - Of man-made fibers:

This HTS category, 6105.20, specifically encompasses men's or boys' shirts that are knitted or crocheted and primarily constructed from man-made fibers. This includes a wide range of synthetic and regenerated cellulose materials such as polyester, nylon, acrylic, rayon, and modal. The garments classified here are designed for wear by males and are manufactured using knitting or crocheting techniques, differentiating them from woven apparel.

The distinction from sibling categories is crucial for accurate classification. Category 6105.10 covers similar men's or boys' knitted or crocheted shirts, but these are specifically made of cotton. In contrast, 6105.20 focuses exclusively on those not predominantly made of cotton, but rather from man-made fibers. Category 6105.90, however, pertains to shirts of "other textile materials," which would typically encompass natural fibers other than cotton, such as wool or silk, that are not covered by the specific man-made fiber classification here.

Within this category of man-made fiber shirts, further subdivisions exist to refine classification based on material composition. Subcategory 6105.20.10 addresses shirts containing 23 percent or more by weight of wool or fine animal hair. This specific threshold is applied to ensure that any significant wool content, even within a predominantly man-made fiber shirt, is appropriately identified. The residual items, not meeting the wool or fine animal hair criteria, fall under the "Other" subcategory, 6105.20.20, representing the broad spectrum of man-made fiber knitted or crocheted shirts.