A shipping unit is a unit of measurement used to measure the amount of goods being shipped. A TON is a unit of weight equal to 2, 000 pounds. A CRATE is a large container typically made of wood or plastic. A CARTON is a box made of paperboard or cardboard. A netton is a unit of measurement for bulk cargo, equal to one metric TON. A carload is a unit of measurement for freight, equal to the amount of freight that can be loaded into a railroad car.