Containers or Shipping containers, Ocean containers
The standard 40 foot long ocean container the size of a 40 foot trailer on a semi truck. The standard size is 40 feet by 8 feet by 8 feet and holds about 5000 pairs of shoes.  There is the half size  20 footer and the Extra Large 40 foot High Cube (about 1 foot taller than the standard 40.
This is the standard unit for ocean freight.   Top selling shoes are ordered by the full container load.

The half size 20 foot shipping container
The half size 20 foot container
40 Foot container truck
40 Foot container truck
Shoe are imported from CHina in huge Container ships
A container ship from China
The container yard
A massive container yard