Tariff Concession Order (TCO 1134871) declares that "double cone valves, sinter plant waste gas mains" (Tariff heading 8481.80.90) are goods to which Item 50 in Part III of Schedule 4 to the Customs Tariff Act 1995 applies, effective 18 Oct 2011 under s.269P and until revoked under ss.269SC/269SD. Mechanically, it lets importers claim the Schedule 4 concession (reducing customs duty) if correctly classified, shifting cost from importers to the revenue and creating a compliance and revocation risk for importers.