Non-Optical Measuring & Checking Instruments and Machines (NESOI)

Classification under 9031804000 requires that the instrument be an electron beam microscope specifically equipped for handling semiconductor wafers or devices. A general-purpose scanning electron microscope without dedicated wafer-handling features would typically classify under heading 9012 (particle-beam microscopes) rather than 9031. The presence of integrated wafer-stage automation and cassette-loading systems is the distinguishing functional criterion.

CBP classifies goods as a whole under the heading that best describes the article's primary function. Equipment designed principally to test electrical characteristics of internal combustion engines falls under 9031808060, while equipment testing other engine characteristics falls under 9031808070. Multi-function test benches are classified by essential character; importers should document the primary design intent and consult a licensed customs broker if the equipment's function is genuinely mixed.