I’ve posted about these before… They are food ration bars that are made primarily to stock lifeboats on sea going vessels and some military applications. They are made by Survivor Industries, Inc. who have been around since the 80’s. I became aware of them in the early 90’s when I serviced a catscan not far from their headquarters in Oxnard CA. https://www.survivorind.com/ Their food ration bars have a shelf life of 5 years with a temperature range of –40˚F to 300˚F. They come in 1200, 2400 and 3600 calorie sizes. They are complete nutrition with all the daily allotment of vitamins and minerals etc. They are also non-thirst provoking. They are designed to feed people in a lifeboat at sea for weeks if necessary. The complete details are here… https://www.survivorind.com/product/mainstay-240024-pack/ These details should answer any question you may have far better than I can. I buy the 2400 calorie bars by the case and usually keep 2 cases around at all times. MS24-20 Mainstay 2400(20 pack) for $94.50, shipping across the US is about $30, they are heavy. That’s a 40-day supply of food for 1 person that doesn’t need to be cooked. The wafers/bars have a lemon flavor, actually quite tasty. The company has many other emergency products which I have not tried. That said I’ve done business with this company for 28 years. My only complaint is that since they are geared toward supplying large shipping companies and militaries around the world their customer service for an individual can be slow, so be patient.