Swap body
A swap body (or swop body) is one of the standard freight containers for road and rail transport. This container type may also be called "exchangeable container" or "interchangeable unit".
Swap bodies take advantage of the large number of trailers used to carry standard ISO containers. The design of swap bodies and roller container is optimized to minimize empty weight, saving on trucking fuel cost (less dead weight to be transported).and cost of built of reloading terminals.