The British RAF had something very similar to these during WW2, known a Horlick’s Tablets or Malties. They were packed 12 to a tin, not unlike an Altoid tin, as a 24 hour emergency ration. You can still find Horlick’s Tablets or Malties on line from specialty candy dealers. They both, Survival Tabs and Horlick’s Malties, taste like malt balls. I think the Survival Tabs would be great if they packaged them as a 24 hour emergency ration, but long term ration. As packed today one box of Horlick’s Malties (original or chocolate) would be a respectable 24 hour iron ration. See photo of original Horlick's...
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