A tariff concession order makes transparent polymethyl methacrylate aquarium windows (tariff classification 3925.20.00) eligible for the Schedule 4 concession listed as Item 50, effective 30 August 2006. Importers pay lower or no tariff on these specific goods and the Commonwealth forgoes the corresponding tariff revenue. The concession was made by a delegate of the CEO under s269P of the Customs Act 1901 and continues until revoked under ss269SC/269SD or a specified expiry; importers must classify and claim the concession on import paperwork.