CPV code 37321600 designates Musical instrument pouches or cases or accessories in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
37321600 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 37321000 (Accessories of musical instruments).