CPV code 34966100 designates Radio Direction Finder (RDF) in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
34966100 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 34966000 (Radio Direction Finder and Non-Directional Beacon).