Definition: Net mass
Net mass is the most common unit of measurement of quantity used in the collection of trade data. It was collected for all headings until 1997. Since then it has not been required for certain categories of goods in intra-EU trade for which it is not the most suitable quantity unit.
The figure of net mass collected is the net mass of the goods without packaging. It is collected in kilograms but in publications the net mass is expressed in tonnes (that is, 1 000 kilograms).
Eurostat, "Statistics on the trading of goods - User guide", Office for Official Publications of the European Communities, Luxembourg, 1998, p. 31