The mark specified by the International Organization for Standardization has two types: mandatory mark and self-selected mark. Each type of mark is divided into an identification mark and a work mark. Specifically, the container has a box main code; box number or sequence number, check number; container size and type code.

A must mark

1. Identification mark. It consists of the box master code, device identification code, sequence number and check digits.

(1) Owner Code. It is the three capitalized Latin letters that the container owner registered with the International Containers Bureau. For example, one of the main codes of the Maersk Group's own box is “MSK”.

(2) Equipment identification code. It is the fourth letter of the main code of the box, which is used to indicate the type of container, the most common is "U", which is used to represent all conventional containers. In addition, "J" means a detachable container, and "Z" means a trailer and a chassis of the container.

(3) The sequence number, also known as the "box number" or "Registration Code", consists of 6 Arabic letters. If the valid digit is not 6 digits, then 6 digits are padded with "0" before the significant digit to distinguish it from the container of the same owner, such as "053842".

(4) Check the numbers. Also known as "Check Digit", the check digit is used to verify the accuracy of the box master code and sequence number record, and is processed by computer. It is located after the sequence number and is represented by an Arabic digit plus a square.