This Tariff Concession Order (TCO 0701601) declares that double‑crystal monochromators (tariff classification 8543.90.90) are goods to which item 50 of Part III of Schedule 4 to the Customs Tariff Act 1995 applies, effective 30 January 2007. The declaration is made under s.269P of the Customs Act 1901 by a delegate of the Chief Executive Officer and remains in force until revoked under ss.269SC or 269SD. Importers should ensure correct classification, apply the Schedule 4 item when calculating customs treatment, and monitor revocation risk.