CPV code 50821000 designates Repair services of boots in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
50821000 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 50820000 (Repair services of leather personal goods).