No, not absolutely........not seeing a tag on the bottle in question while it was in use and not having seen a warning label on them in the store, I will have to say that the above statement may be in error.
Par Si Vis Pace Para Bellum
1. I assume that most of you are back sleepers, hence the femoral location of the warm bottle.
For us side-sleepers, does anyone have strong feelings as to...front side vs backside?
2. Anyone else here ever destroy a KleenKanteen? Anyone? Anyone?
I have. Left about 1 inch of citrus flavored sugar-free drink (mixed) in one that was in a crate in my vehicle. Ate pin-holes all around the perimeter at the liquid level. I would never have thought......
Since the fuel-centered hand warmers use combustion, they must also produce carbon monoxide and other nasties. A friend of my recently related story of army days when he zipped himself inside a mummy bag with a zippo hand warmer (years ago) and just about died trying to escape when the fumes got bad.
I'd be pretty leary of taking one to bed where I was sleeping. When awake and mobile, alert, not a problem, perhaps. But sleeping and unconscious, I'd be pretty wary. Just saying....
Things fall apart, the centre will not hold
They last 18+ hours. I've used them all night then got up in the morning and they are still warm enough to keep my hands warm as I eat breakfast and break camp.
I did the same thing with a non-insulated stainless steel bottle . The temps were way below freezing (probably in the teens) I have no under quilt just a self inflating pad and a 30* bag. That hot watter bottle turned a potentially miserable night into a very comfortable one. My bottle stayed warm for about 5 hours so I reheated it and slept comfortably the rest of the night.
How about 2 stainless steel uninsulated bottles one for your back and one for the front?