Heading 9011 is limited to compound optical microscopes that use visible light. A scanning electron microscope uses an electron beam rather than light to form an image, so it classifies under 9012 regardless of any optical viewing components it may include for alignment purposes.

Many electron microscopes and diffraction instruments are dual-use goods controlled under the Commerce Control List. Exporters must check EAR licensing requirements, and some destination countries require import permits. Consult a licensed customs broker or trade-compliance counsel before shipping.