Fittings are connective components designed to join, redirect, or terminate pipe runs — such as couplings, elbows, tees, reducers, and sleeves. Valves, which control flow, are classified in a different chapter covering industrial valves and taps. If an article both connects and controls flow, its principal function determines classification.

Any fitting made from a copper-zinc alloy (brass) falls under 741220 as a copper alloy fitting, not under 741210 for refined copper. The distinction matters because duty rates and any applicable trade-remedy measures may differ between the two subheadings.