CPV code 39715100 designates Electric instantaneous or storage water heaters and immersion heaters in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
39715100 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 39715000 (Water heaters and heating for buildings; plumbing equipment).