What 20GP, 40GP, 40HC and open-side actually mean, how the size-type codes are read, and which one of these we build ourselves on our own line in Pingshan.
Every container carries a four-character size-type code, and once you can read it you never have to ask what a box is again.
The first character is length. The second is height and width. The third and fourth are the type — what the box is built to do.
So 20GP is a 20-foot general purpose box at standard height. 40GP is the same thing at 40 feet. 40HC is a 40-foot high cube: same footprint as a 40GP, taller inside.
The code is defined by ISO 6346, which also governs the owner prefix and serial number on the door.
A 20-foot general purpose container is the workhorse of containerised freight, and it is the box we build on our own line.
Inside: 33.2 m³. Payload 28,295 kg. The panels are weathering steel, the floor is 28 mm, and every box carries a CSC safety approval plate.
Why 20 ft rather than 40 ft dominates for dense cargo is simple arithmetic: a 40-foot box gives you roughly double the volume for a payload that is not double. Load anything heavy and you reach the weight limit in a 40 with the box half full, which is why steel, tiles, machinery parts and minerals move in 20s.
A 40GP doubles the length and gives you roughly double the internal volume. It is the standard for cargo that fills before it weighs.
A 40HC — high cube — has the same footprint as a 40GP and about 30 cm more internal height. That extra height is worth having if your goods stack in a way that uses it, and worth nothing if they do not. It also raises the loaded height of the vehicle underneath it, which matters where clearances are tight.
These are reference figures for load planning. We build the 20 ft box; we do not supply 40GP or 40HC.
Beyond the general purpose range there are boxes built for particular problems: open-side units that open along the full length for loads that cannot be handled through a door, open-top units for cargo that has to be craned in, flat racks for over-width and over-height loads, and reefers for temperature-controlled freight.
Each of those is a different product with a different certification path and a different set of suppliers.
We do not supply any of these. They are listed because a loading plan sometimes needs them.
We build one box: the 20 ft general purpose dry cargo container, on our own line, plated to CSC.
The 40GP, 40HC, open-side, open-top, flat rack and reefer entries above are reference for planning a load. We do not build them.
If the 20 ft box is what you need, start with the specification, then the supply terms.
