Customs classification of mounted prism components followed the parent machine where the goods were ready for use and tariff timing mattered.

Mounted prisms imported for binocular heads were held classifiable as parts and accessories of the binocular head under Heading 90.11/12, not as separate prisms under Heading 90.01. The goods were found to be mounted and ready for use, and that factual position was not displaced. The tariff basis relied on by the Revenue, drawn from later HSN sub-notes, was held inapplicable to the tariff position existing at the time of import. The classification also accepted reliance on technical material and laboratory opinion in resolving the dispute, and the Collector's classification was upheld while the Revenue's challenge failed.

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Issues: Whether imported mounted prisms for binocular heads were classifiable as parts and accessories of binocular heads under Heading 90.11/12, or as prisms under Heading 90.01.

Analysis: The imported goods were found to be in mounted condition, ready for use, and the factual statement to that effect was not displaced. The tariff entry relied upon by the Revenue on the basis of later HSN sub-notes was held to be inapplicable to the tariff position prevailing at the time of importation. The reasoning also accepted that technical material and laboratory opinion could be relied upon in classification matters, and that the cited authorities supported classification of goods as parts and accessories with the parent machine where appropriate.

Conclusion: The classification adopted by the Collector was upheld and the Revenue's challenge failed.

Final Conclusion: The imported goods remained classifiable as parts and accessories of the binocular head, and the Revenue appeal was rejected.

Ratio Decidendi: For customs classification, goods that are mounted and ready for use as components of a specific machine may be classified with the parent machine where the relevant tariff entry at the time of import supports such treatment, and technical expert material may properly be relied upon.

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