7320.90 - Other:

This category, "Other," within HTS code 7320.90, encompasses springs and leaves for springs made of iron or steel that do not fall under the more specific classifications of leaf springs or helical springs. It serves as a residual category for a variety of spring types and related components that are not explicitly defined by other headings within 7320.

Distinct from its siblings, 7320.10 covers specifically leaf springs, which are composed of multiple flat bars of metal stacked together, and their individual components. Similarly, 7320.20 is reserved for helical springs, characterized by their coiled or spiral shape. Therefore, 7320.90 is intended for any iron or steel springs that do not fit these distinct configurations, such as volute springs, spiral springs (not helical), or specialized spring washers.

The subdivisions within 7320.90 provide further clarity for classifying these remaining spring types. The subcategory 7320.90.10.00 specifically identifies hairsprings, which are extremely fine springs used in timepieces and other precision instruments. The remaining "Other" subcategory, 7320.90.50, captures all other residual iron and steel springs and spring leaves not otherwise classified within the 7320 heading.