Shipping containers are standardized metal boxes that can be hauled by ships, trains, and trucks. Shipping containers are used to transport everything from produce to heavy machinery. Three types of shipping containers exist: the dry container, refrigerated container, and tank container. In addition, two features standardize containers: their size and corner castings. The dry containers are typically 53′, 48′, 40′, and 20′; refrigerated containers are usually 53′ or 48′; tank containers are usually 20′.

Corner castings allow cranes, freight cars, and trucks equipped with twistlocks to secure any container from any country. All containers have a minimum of eight corner castings molded into the corners of the container. The idea of shipping containers is simple: these containers standardize the transport of goods across the globe. For example: a company in Japan wants to send parts to a company in Florida. Unloading and loading the parts from vehicle to vehicle would likely damage some of the cargo. But by using shipping containers, the Japanese manufacturer could avoid damage to the parts. First, the Japanese company would fill the container with parts. A trucking company would drive the container to a port where it would be loaded onto a ship. The ship would take the container to a port on the West Coast of the U.S.. Another company would load the container onto a train, and the container would be hauled to Florida. A port in Florida would unload the container from the train and place it on a truck. Finally, a trucker would drive the container to the final destination.

The parts would have arrived at their destination without anyone ever having to open the container. Because shipping containers are a world standard, they have stimulated world trade more than any invention since the steamboat.