| Contract date | Snap | Reinforcement | Sewing Type | Back Webbing | Drain Hole |
|---|---|---|---|---|---|
| 1968 | Plastic | none | M1956 type | hard thick nylon webbing, brown | none |
| 1972 | Metal | none | M1956 type | hard thick nylon webbing, green | none |
| 1974 | Metal | ears and body | ALICE type | safety cord, green | one |
