At the SITC level, all base-metal castors fall here regardless of load rating or wheel composition. At the HTS 10-digit level, however, subheadings may distinguish by construction details. Importers should review the HTS schedule notes and, if the castor incorporates non-metal wheel materials (e.g., rubber or polyurethane treads), confirm whether the essential character remains base metal for classification purposes.

Castors are specifically defined as wheeled devices designed to be attached to the underside of objects to allow movement. Misclassifying them as wheels, rollers, or furniture parts can result in incorrect duty rates and potential CBP penalties. A binding ruling request is a reliable way to secure classification certainty for high-volume castor imports.