After Korea, C-Rations were changed once again to what would be the final form of this type of combat ration. The number of individual meals were increased from 6 to 12 per case. The case became slightly larger 1.3 cubic ft. compared to 1.1 for Korean war cases, and once again the weight was reduced from 38 to 35 pounds. The steel strapping was replaced with clear nylon, having been reduced a full 10 pounds in weight from WW II yet in the same sized case, they still contained "old standbys" like ham & lima beans, spaghetti & meatballs and still had accessory packs. 
Tactical conditions in Vietnam called for the use of long range recon patrols. In order to travel light "LRRP" rations were introduced that had been developed from the space program. These evolved into MRE's that are currently in use.  
Eash box set comes with instructions on scoring, cutting, folding and gluing, along with a list of helpful tools.