Tariff classification of waveguides under Heading 85.44 turned on analogy with co-axial cables under Rule 4.

Imported waveguides supplied in running lengths and intended for microwave transmission were not covered by Heading 85.25 because they were not transmission apparatus of that kind, but only formed part of a transmission system after use. Heading 83.07 was also inapplicable because it concerns flexible or corrugated tubing used for watertight protection or as conduits for fluids and similar purposes, which did not match the goods' function. As no specific heading applied, Rule 4 of the Rules for the Interpretation of the Customs Tariff required classification under the heading to which the goods were most akin. The waveguides were therefore classified under Heading 85.44, specifically sub-heading 8544.20, by analogy with co-axial cables.

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Issues: Whether the imported waveguides were classifiable under Heading 83.07, Heading 85.25, or Heading 85.44, and whether Rule 4 of the Rules for the Interpretation of the Customs Tariff applied to classify them as goods most akin to co-axial cables.

Analysis: The goods were imported in running lengths and were meant to function as microwave waveguides for transmission of electromagnetic waves. Heading 85.25 was held inapplicable because the goods did not constitute transmission apparatus of the kind specified therein, but only became part of a transmission system after use. Heading 83.07 was also rejected because that heading covers flexible or corrugated tubing used for watertight protection or as conduits for fluids and similar purposes, which did not match the actual use of the goods. The goods were not specifically covered by any other heading, and their function was found to be similar to co-axial cables falling under Heading 85.44. Applying Rule 4, goods not classifiable under the preceding headings are to be classified under the heading to which they are most akin.

Conclusion: The waveguides were correctly classifiable under Heading 85.44, specifically under sub-heading 8544.20, and not under Heading 83.07 or Heading 85.25.

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