Customs tariff amendments update exemption entries by substituting specific HS classification codes in existing notifications. Amendments substitute specified HS tariff subheadings in the Tables of four customs exemption notifications: two entries are replaced with '8529 90 30 or 8529 90 90' and two entries with '8529 90 10 to 8529 90 30', by identifying each principal notification and the relevant serial number and substituting the new entry in column (2). The amendments are effected under the executive power to amend notifications in the public interest under the Customs Act.