It’s container size and type, please find the normal bore size and cubage as below:
20GP: L:5900MM W:2340MM H:2380MM CBM:29
40GP: L:12000MM W:2340MM H:2380MM CBM:60
40HQ: L:12000MM W:2240MM H:2680MM CBM:65
Note: Above information just for your reference, how many cargo you actually can stuff will depend on your package size, stuffing method, etc.