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The importance of container markings

Used containers, container rental, container leasing, container purchase.

You might have seen some alpha-numeric sequences on containers. Ever wondered what they mean? These sequence markings are known as Container Markings. They are important for the monitoring and general safety of a container. Let’s have a look at each of these container markings individually to get an idea of what they mean and why it is needed.

Compulsory Container Markings

container markings


The container number is a unique set of four letters and seven numbers to identify containers internationally. It is assigned by the classification agency ISO.

  • The first three capital letters are the Owner’s prefix, which must be unique. Here, the VST stands for the VS&B Containers group.
  • Then comes, the Equipment category identifier which is “U” for this container and stands for freight containers. Other categories are:
  • The letter “J” implies detachable freight containers related equipment,
  • The letter “Z” implies trailers and chassis,

Together with the owner code, this category can be grouped under one term, known as an alpha prefix.

  • Serial number or registration number consists of six digits and is left to the owner to decide on.
  • The last number of the container number is placed separately from the rest of the numbers on the right side and is called a Check Digit. This is to verify whether the numbers were accurately entered. The data processing system will reject if the check digit does not match. This was built in to reduce the number of errors when copying container numbers.


Each container is given a unique ISO code by the BIC (Bureau International des Containers) to avoid problems in naming the container. Why? Because of a 20ft. standard container, for example, is called a dry van, general-purpose, or dry container in different countries.

mandatory additional container markings

Mandatory Markings

Mandatory markings provide visual warnings concerning the weight of containers, overhead electrical danger, and for containers higher than 2.6m.

Container markings are put on the door of a shipping container, but the Identification number and the Size and type code are displayed on both sides so that it would be visible for crane operators, transporters, authorities, and forklift operators.


At VS&B, we have a fleet of over 30,000 containers, for leasing and sale with new containers being built every month, of course, with the requisite markings.


VS&B Containers, headquartered in Chennai, began operations in 1996. The company offers a wide variety of containers, both newly built and used, and custom-built units that can be directly shipped from our manufacturing facilities to your preferred destinations across the world. We also operate a leased fleet of over 30,000 containers for both international leasing and domestic leasing (within India). If you have container requirements, do drop us an email at and a member of our team will reach out to assist you.  

Furthermore, iInterchange Systems (A VS&B group company) provides state-of-the-art software solutions tailored specifically to meet the needs of container shipping and logistics enterprises. Please visit or drop us an email at for more details.