This Tariff Concession Order (TCO 0825386) treats a specific ring-spun yarn (HS 5509.53.00 — at least 67% polyester, up to 33% cotton) as falling under Item 50, Part III of Schedule 4 to the Customs Tariff Act 1995, effective 7 Aug 2008.
Mechanically, the Order changes how customs duty is applied to imports of that yarn (reducing or removing the duty for affected importers). It was made by a CEO delegate under s269P and can be revoked under ss269SC or 269SD; the main actors are importers (who pay less), the Treasury (foregone revenue) and customs (administration/compliance).