This Tariff Concession Order (made under s.269P) applies Schedule 4, item 50 of the Customs Tariff Act 1995 to goods classified at tariff 7306.61.00 described as “ducts, rectangular hollow profiles, steam generation plant”, effective 7 October 2008 until revoked. Mechanically, it changes the customs duty treatment for those specific imported goods: importers pay reduced or altered duty while the order is in force, Customs delegates administer eligibility, and importers must correctly classify and document the goods to claim the concession.