Replacement probes, sensor elements, capillary tubes, protective sheaths, and other components dedicated to the meteorological and physical-measurement instruments of the parent heading are classified here when they are identifiable as suitable for use solely or principally with those instruments. The heading's scope mirrors the breadth of the parent — covering parts for everything from simple glass thermometers to industrial pyrometers — so the dedicated-use determination and the nature of the component (mechanical, electronic, or optical) guide correct classification. Generic electronic sensors or display modules that serve multiple instrument types are typically classified under their own functional headings.

AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.