40' Dry Containers comes in 2 height, one is the normal 8'6" and the high cube 9'6". The easy way to differentiate the 2 type is by looking at the height sticker which is pasted on the high cubes on all the top corners of the container. Thus if there is no height sticker on the corner, it means it is the normal 8'6" container.
20' Dry container are usually used for containing heavier cargoes as the max gross weight for the 20' and 40' are actually the same at 32,500 KG.
If the load is extremely heavy, then the shipper might want to use a special container called the Flat Rack instead.
Above is a flat rack
What about Food, Medical and Sensitive Cargo??
Shipper could request for a food-grade dry container for them if they will not be affected by the temperature.
But if cargoes like the perishable goods which will be affected by temperature, humidity and other environment factors, shipper will requires a Refrigerated Container Box (Reefer Box). The Reefer Box is very different from normal dry containers as they comes with a cooling machinery which allows shippers to adjust the atmosphere within the container. They can pre-set the best environment in the box before loading the cargo into the box to allow the cargoes to last through the trip.
Above is a Reefer Container
Conclusion
The type of container used by a shipper is depending on the quantity and type of cargo they want to ship.
