Cause normally, they suck. Some don't heat, they are fussy, small, etc.
But this weekend I was issued out some spare training meals, and they came with this totally other heater. Same principle: bag, water, heat. But this is what they should be!
- It is big. Around 9x16" so you can fit most of an MRE in there, or heat other stuff easily.
- In there. No bullshit to arrange the heater below the meal, sorta stuffed into something else, etc. Plenty of room, so toss the meal in the bag.
- It gets HOT. And stays that way.
- You can tell it works. A few seconds after pouring the water in, it goes POOF! so energetically it's not far from an explosion. But you know it's working.
They also claim the water is 99% pure, I guess indicating you can pour more water in there once the reaction starts, and get boiled/purified water from it, which would be cool if true. Or, just cook things like soup, boil noodles, etc. directly in it. Will try that sometime.
It had enough writing I was able to contact someone who sent me somewhere else and you can buy them alone:
(Note their store is stupid. You can buy other quantities than 12)
I am totally getting a few for myself. Gonna replace my stove (or even triox tablets) for most heating purposes when weight and bulk is important (i.e. a lot of the time).
Next, I am going to try to find out where you can get the Cooking Bags on that chart. 60 minutes of this? That would even more strongly replace a stove for occasional use.