ISO containers are standardized re-usable steel shipping enclosures, designed for safe, efficient, and secure storage and movement of goods.

There are a number of ISO standards that regulate many aspects of freight containers from the classification, dimensions, to corner fitting specifications, to hooks for lifting the containers, to the markings/identification on the container. These standards make transportation and handling simpler and standardized. Standard footprints of these containers for use as data center modules are: 20 ft and 40 ft.