8504.50 COILS, toroidal, having ALL of the following: (a) winding wire dia NOT exceeding 0.25 mm; (b) internal window dia NOT exceeding 40 mm; (c) external dia NOT exceeding 55 mm Op. 17.06.1985 Dec. 13.01.1986 - TC 8532473
8504.32 AUTOTRANSFORMERS, toroidal core, continuously variable from zero voltage Op. 01.01.1988 Dec. 01.01.1988 - TC 8734825