6108.39.40.00 - Containing 70 percent or more by weight of silk or silk waste (751)

This HTS category, 6108.39.40.00, specifically classifies knitted or crocheted nightdresses and pajamas that are composed of other textile materials, with the critical defining characteristic being that they contain 70 percent or more by weight of silk or silk waste. These garments are intended for sleepwear and are designed for women or girls, aligning with the broader scope of Chapter 61, which covers knitted or crocheted apparel.

This classification is distinguished from its siblings by its precise material composition. It is separate from 6108.39.10.00, which covers similar garments made from wool or fine animal hair. It also differs from 6108.39.80.00, which serves as a residual category for nightdresses and pajamas of other textile materials that do not meet the specific silk content requirement of this subcategory.

As this is a leaf node within the HTS structure, there are no further subcategories. Therefore, classification within 6108.39.40.00 is definitive once the criteria of being a knitted or crocheted nightdress or pajama for women or girls, and containing 70 percent or more by weight of silk or silk waste, are met. This ensures accurate tariff application based on the primary material content.