SECU, Stora Enso Cargo Unit, is a type of intermodal container (shipping container) built to transport bulk cargo like paper on railway and ship.
The ports used are mainly in production countries like Finland (Kotka, Oulu) and Sweden (Gothenburg) and in consumer countries Belgium (Zeebrugge), UK (Tilbury, Immingham) and Germany (Lübeck).
The benefit is that their larger capacity reduces the number of containers needed, and therefore their handling cost.
They can be transported on truck ferries, but do not fit normal container ships.
The Stora Enso Cargo Unit has fixed legs so that the inner floor has a height of 874 mm (34.4 in) for an unloaded container - the basic container (without legs) has outer dimensions of 3,600 mm (11 ft 10 in) squared.