>>527360>There's re-usable hand warmers too. Not sure if you think they are too weak, but you can even Re-set them by cooking them a few minutes the next morning.I have a pair of these (pic related) and they don't get very warm, I found them pretty useless when ice fishing.
I also have a Jon-E hand warmer and while that does get quite warm, (even too hot) it tends to go out fairly often, requiring relighting.
