 A | Unit container provides level A packing protection. |
| B | Unit container provides level B packing protection. |
| C | MIL-STD-2073-1B/2C Code: Unit container provides level C packing protection. |
| D | MIL-STD-2073-1D Code: No container is required. |
| M | MIL-STD-2073-1D Code: Unit container provides minimal packing protection (see 5.4). |
| O | Unit container is not an acceptable shipping container. |
| Z | Unit container requires special consideration (air only, inside storage only, etc.) |