The original milvans (Military cargo vans). These are 88" x 108" x 108" Developed in the 1960's by the military, the first extensive use was in SE Asia during the Vietnam conflict. At the same time commercial interests were developing a larger container. Eventually 2 standard sizes were established for international travel: 20' and 40'. Domestic containers also come in larger 48' and 53' lengths for trucks and trains.
The USAP uses 20' containers.
Many of the USAP containers are orange.
Standard 20' international shipping container (TFE).