Auxiliary duty exemption on machinery component imports limits duty to that on the completed article, subject to proof and conditions. Exemption limits auxiliary duty on component parts imported for initial setting up, assembly or manufacture of specified machinery to the amount not exceeding that leviable on the completed article, subject to proof to the Assistant Collector of Customs and the conditions specified in a prior notification; applicability is confined to parts and articles listed by heading, with stated inclusions and exclusions and use-based qualifications.