CPV code 31671000 designates Glass envelopes and cathode-ray tubes in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
31671000 sits under 31670000 (Electrical parts of machinery or apparatus) and groups 2 more specific sub-codes. When classifying a tender, choose the narrowest code that still covers the full subject of the contract.