NAICS 33429 includes products such as intercom and paging systems, radar and sonar equipment, radio navigation aids, search and detection apparatus, and other specialized communications hardware that does not primarily function as a telephone or broadcast/wireless device. Marine electronics, air traffic control equipment, and industrial two-way radio systems are common examples.

Radar, sonar, and radio navigation equipment generally classify under HTS Chapter 85 headings covering direction-finding, radio-navigational aid, and detection apparatus. The correct subheading depends on the operating principle, frequency, and intended application — distinctions that matter because duty rates and any applicable trade-remedy exposure differ across subheadings. A licensed customs broker with electronics classification experience should review the technical specifications.