3920.99 - Of other plastics:

This HTS category, 3920.99, encompasses plates, sheets, film, foil, and strip made from "other plastics." This designation applies to products manufactured from plastic materials not specifically enumerated in preceding subheadings within 3920.91 through 3920.94. Therefore, it serves as a residual category for a wide array of noncellular, unsupported plastic forms that do not fall under poly(vinyl butyral), polyamides, amino-resins, or phenolic resins.

Crucially, this category distinguishes itself from its siblings by the absence of specific polymer identification. While 3920.91 focuses on poly(vinyl butyral), 3920.92 on polyamides, 3920.93 on amino-resins, and 3920.94 on phenolic resins, 3920.99 captures all other plastic compositions. The physical form – plates, sheets, film, foil, and strip – and the absence of reinforcement, lamination, or other composite structures with different materials are common to all these sibling categories.

Within 3920.99, further distinctions are made based on flexibility. The primary subdivision, 3920.99.50.00, covers "Other" materials. This often implies a further breakdown, not explicitly detailed at this level, that may distinguish between rigid and flexible forms, or based on specific applications or dimensions of the plastic products within the broader "other plastics" definition.