A crate is a large shipping container, often made of wood, typically used to transport or store large, heavy items. Steel and aluminium crates are also used. Specialized crates were designed for specific products, and were often made to be reusable, such as the "bottle crates" for milk and soft drinks. Crates can be made of wood, plastic, metal or other materials. The term crate often implies a large and strong container. Most plastic crates are smaller and are more commonly called a case or container. Metal is rarely used because of its weight. When metal is used, a crate is often constructed as an open crate and may be termed a cage. Although a crate may be made of any material, for these reasons, the term 'crate' used alone often implies one constructed of wood. Wooden crates A wooden crate has a self-supporting structure, with or without sheathing. For a wooden container to be a crate, all six of its sides must be put in place to result in the rated strength of the container. Crates are distinct from wooden boxes. The strength of a wooden box is rated based on the weight it can carry before the top (top, ends, and sides) is installed, whereas the strength of a crate is rated with the top in place. In general conversation, the term crate is sometimes used to denote a wooden box. History Crates had been used for many years without a clear origin in documented history. Modern crates from the early 20th century demonstrate a very evolved technology already considering practical and economic considerations built into crate designs. Moving heavy products such as enamelled cast iron sinks, bath tubs, and lavatories was often done without any packaging prior to 1910, which lead to nearly 20% losses due to chipping of the enamel in shipping. Some manufacturers assumed that protecting the product in rugged crating would reduce their losses, however, they found that railroad and shipping workers would handle the crates much more roughly when in a heavy crate, and losses actually increased. The technological solution was to pack enameled bathware into open crates, which allowed the shipment to be lighter and cheaper, the handlers to use more precautions knowing what merchandise was being shipped, and allowed the customer to inspect the purchase at arrival before opening it. Another early documented reference to a shipping crate in the United