Certain measuring tools in this category have been subject to antidumping investigations targeting specific countries of origin. Importers should search the International Trade Administration's antidumping and countervailing duty order database for the specific product description and country before importing, and request a scope ruling from the Department of Commerce if the product's coverage is uncertain. Scope determinations can turn on fine distinctions such as jaw material, resolution, or intended use.

Hand-held calipers and micrometers classified here are manually operated, single-axis instruments used for direct dimensional measurement. Coordinate measuring machines are multi-axis, typically bench- or floor-mounted systems that map three-dimensional geometry and are classified under a separate heading for measuring or checking machines. The hand-held, single-measurement-axis character is the defining feature for classification in this heading.