Camel-back strip is an unvulcanized rubber compound extruded in a profile designed to be applied to the crown of a worn tire casing during the retreading process. It receives its own subheading (400610) because of its specific commercial function in the retreading industry, distinguishing it from general-purpose unvulcanized rubber shapes.

The key distinction is form: 4005 covers compounded rubber in primary forms (pellets, granules, crumbs) or flat plate, sheet, and strip. Once the material has been further worked into a rod, tube, profile, disc, ring, or other three-dimensional article, 4006 applies. Consult a licensed customs broker for borderline extruded profiles.