Each owner key is unique –
Container labelling
according to international standard ISO 6346

What do the different container numbers and prefix numbers actually mean?

For example
OHHU 602020 0

The first three letters indicate the owner of the container, there is no systematic meaning.
The fourth letter indicates the use of the container, e.g. U for universal use.
This is followed by a 6-digit identification number of the owner.

The last digit is a check digit. It is calculated from the operator code, use code and the
the identification number. If, for example, an incorrect identification number was entered when
the bill of lading was created, this is immediately detected by the check digit.

The prefix is assigned only once worldwide and is assigned by BIC in Paris.
After manufacture, each container receives an inspection sticker from an internationally approved
inspection company, a “CSC plate” (International Convention for Safe Containers).
The CSC plate is valid for a period of 5 years and must then be renewed
accordingly. Containers without this plate may not be used in maritime transport.

Interesting facts:
Sea containers are in use worldwide (approx. 22 million).
Service life (approx. 20 years).
They can be stacked up to 6 high.
There are about 9000 container ships, the largest of which is 24000 TEU.