The combination reflects shared production inputs — primarily steel wire rod — and overlapping manufacturing processes. Many establishments produce both spring forms and other wire fabrications on similar equipment, making a combined grouping practical for statistical and trade-flow reporting purposes.

Importers should have mill certificates or material test reports confirming steel composition, a commercial invoice specifying product type and dimensions, and a packing list. If the goods originate from a country subject to Section 232 measures, documentation supporting any claimed exclusion or quota allocation is also required.