9404.21.00 - Of cellular rubber or plastics, whether or not covered

This HTS category, 9404.21.00, specifically covers mattresses that are constructed from cellular rubber or plastics. These materials can be integral to the mattress construction or serve as a filling, and the mattress may be covered by various textiles or other outer materials. The key distinguishing factor for this classification is the primary composition of the mattress core.

In contrast to its sibling category, 9404.29, which covers mattresses made from "other materials," this heading exclusively addresses those made from cellular rubber or plastics. Therefore, if a mattress's primary cushioning or structural component is derived from foam-like rubber or plastic, it will fall under 9404.21.00, regardless of any textile covering.

Within this category, further distinctions are made by subcategories to refine classification based on specific attributes. For example, 9404.21.00.10 distinguishes mattresses intended for use in cribs or toddler beds, acknowledging specialized safety and design requirements. Other subcategories, such as 9404.21.00.13, provide detailed dimensional criteria, while 9404.21.00.95 serves as a residual category for all other mattresses of cellular rubber or plastics not otherwise specified. These subdivisions allow for precise tariff application based on the particular characteristics and intended use of the product.