US domestic standard containers are generally and (rail and truck). Container capacity is often expressed in twenty-foot equivalent units (TEU, or sometimes "teu"). An equivalent unit is a measure of containerized cargo capacity equal to one standard (length) × (width) container. As this is an approximate measure, the height of the box is not considered. For instance, the "high cube" and the "half height" containers are also called one TEU. 48' containers have been phased out over the last ten years in favor of 53' containers.