UNSPSC is the acronym for the United Nations Standard Products and Services Code. UNSPSC was jointly developed by the United Nations Development Programme (UNDP) and Dun & Bradstreet Corporation in 1998 and is currently managed by GS1 US, which is responsible for overseeing code change requests, revising the codes and issuing regularly scheduled updates to the code.
Unfortunately, the system often has errors which result in orphaned codes, or branches that do not go down to the bottom of the hierarchy. This means it is often a manual exercise to ensure a correct upgrade from one version of UNSPSC to another version, unless you use cross mapping from a more detailed system such as NSV or e2class.
There are around 20,000 classifications in UNSPSC.