Heading 7217 covers wire in its drawn or coated form, not yet fabricated into articles. Once the wire is further worked into products such as nails, staples, barbed wire, woven mesh, or strand, it moves to the appropriate finished-goods heading in Chapter 73 or elsewhere.

Subheading 721720 covers wire that is zinc-plated or zinc-coated by any method — hot-dip or electrolytic. Wire coated with a different base metal (copper, tin, etc.) goes to 721730, and wire with other finishes or combinations not covered by 721720 or 721730 falls into the residual 721790. The coating metal, not the process, is the primary classifier.