CPV code 33156000 designates Psychology testing devices in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
33156000 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 33150000 (Radiotherapy, mechanotherapy, electrotherapy and physical therapy devices).