Key variables include the container's capacity (typically measured in liters or milliliters), whether it has a ground or unground mouth, and its intended use (e.g., pharmaceutical versus food-grade). These distinctions map to different 10-digit HTS lines with potentially different duty rates, so precise volume and mouth-finish specifications should be confirmed before entry.

Glass containers intended as primary pharmaceutical packaging — such as vials, ampoules, and syringes — may be subject to FDA oversight as medical devices or drug packaging components. Importers should confirm whether the specific article triggers FDA review and ensure the foreign manufacturer meets applicable quality standards.