When the Ever Given became stuck in the Suez Canal, the megaship was carrying 18,300 rectangular, steel boxes on her back. In the weeks and months after the incident, the concealed contents of the shipping containers – stuck in legal limbo – captured global attention. Technologically developed in the years after the Second World War, the standardized shipping container has featured as one of the protagonists of the transformations in international trade. But the container’s logic of concealment and transaction has made ‘the box’ a common figure also in popular culture and social theory. This essay interrogates the shipping container’s multiple repertoires by focussing on containers at work. By tracing how the shipping container moves through the port infrastructure this essay takes us from the Suez Canal towards another central maritime passageway: the Strait of Gibraltar. This essay reflects on the different scales at which the shipping container functions in the port: from heavy materiality to abstracted codes and units of measurement.