This Tariff Concession Order declares that a narrowly defined class of non-slam check valves (Customs classification 8481.30.00) — air-flow valves tested to American Petroleum Institute Standard 598 with a bore of at least 500 mm — are goods to which Part III, Schedule 4, item 50 of the Customs Tariff Act 1995 applies, effective 09.04.08 until revoked. The decision was made by a delegate of the CEO under s.269P; importers of these valves are affected because their tariff treatment is set by the referenced Schedule 4 item and compliance requires the valves meet the specified technical criteria.