In the shipping industry, container prefixes are a series of letters that are used to identify the type of container being used to transport cargo. These prefixes are typically four letters long and are assigned by the International Organization for Standardization (ISO). There are many different types of containers used in the shipping industry, including dry containers, refrigerated containers, and tank containers. Each type of container has a unique prefix that is used to identify it.

For example, the prefix for a 20-foot dry container is "CSCU," while the prefix for a 40-foot refrigerated container is "CFRU." These prefixes are used on shipping documents and bills of lading to identify the type of container being used to transport the cargo.

In addition to identifying the type of container, container prefixes can also indicate the ownership of the container. For example, containers owned by shipping companies may have a prefix that begins with "CS," while containers owned by leasing companies may have a prefix that begins with "PL."

Overall, container prefixes are an important part of the shipping industry, as they help to identify and track the movement of cargo around the world.