CPV code 34512800 designates Tanker ships in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
34512800 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 34512000 (Ships and similar vessels for the transport of persons or goods).