This Tariff Concession Order declares corrugated polyvinyl chloride cooling‑tower sheets (tariff line 3926.90.90) are covered by item 50 in Part III of Schedule 4 to the Customs Tariff Act 1995, effective 27 April 2010 until revoked (issued under s 269P of the Customs Act 1901). Mechanically, it changes the customs treatment of those imports so importers can rely on Schedule 4 item 50; this shifts who pays customs charges, imposes a classification/compliance task on importers, and rests on a delegate’s administrative declaration (Michael Perry).