List of supplementary units (SU) or volume physical units is a code list used respectively in CN and PRODCOM List.
For certain goods, a supplementary quantity is provided in addition to the net mass. This quantity is expressed in a unit, which provides useful information. Supplementary units are units other than kilograms such as, for example, litres, numbers of pieces, carats, terajoules or square metres. Supplementary unit varies according to the goods.
Supplementary units is maintained by Eurostat and published by the Publications Office of the European Union on the EU Vocabularies website.